* Boston, MA 02111-1307, USA.
*/
+/* Prelude {{{1 ----------------------------------------------------------- */
+
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
- * GLib at ftp://ftp.gtk.org/pub/gtk/.
+ * GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
-/*
+/*
* MT safe
*/
+/* implement gthread.h's inline functions */
+#define G_IMPLEMENT_INLINES 1
+#define __G_THREAD_C__
+
#include "config.h"
+#include "gthread.h"
+#include "gthreadprivate.h"
+
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
+#ifndef G_OS_WIN32
+#include <sys/time.h>
+#include <time.h>
+#else
+#include <windows.h>
+#endif /* G_OS_WIN32 */
+
#include <string.h>
-#include "galias.h"
-#include "glib.h"
-#include "gthreadinit.h"
-
-#if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
-# define g_system_thread_equal_simple(thread1, thread2) \
- ((thread1).dummy_pointer == (thread2).dummy_pointer)
-# define g_system_thread_assign(dest, src) \
- ((dest).dummy_pointer = (src).dummy_pointer)
-#else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
-# define g_system_thread_equal_simple(thread1, thread2) \
- (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0)
-# define g_system_thread_assign(dest, src) \
- (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD))
-#endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
-
-#define g_system_thread_equal(thread1, thread2) \
- (g_thread_functions_for_glib_use.thread_equal ? \
- g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\
- g_system_thread_equal_simple((thread1), (thread2)))
-
-GQuark
+#include "garray.h"
+#include "gbitlock.h"
+#include "gslist.h"
+#include "gtestutils.h"
+#include "gtimer.h"
+
+/**
+ * SECTION:threads
+ * @title: Threads
+ * @short_description: thread abstraction; including threads, different
+ * mutexes, conditions and thread private data
+ * @see_also: #GThreadPool, #GAsyncQueue
+ *
+ * Threads act almost like processes, but unlike processes all threads
+ * of one process share the same memory. This is good, as it provides
+ * easy communication between the involved threads via this shared
+ * memory, and it is bad, because strange things (so called
+ * "Heisenbugs") might happen if the program is not carefully designed.
+ * In particular, due to the concurrent nature of threads, no
+ * assumptions on the order of execution of code running in different
+ * threads can be made, unless order is explicitly forced by the
+ * programmer through synchronization primitives.
+ *
+ * The aim of the thread related functions in GLib is to provide a
+ * portable means for writing multi-threaded software. There are
+ * primitives for mutexes to protect the access to portions of memory
+ * (#GMutex, #GStaticMutex, #G_LOCK_DEFINE, #GStaticRecMutex and
+ * #GStaticRWLock). There is a facility to use individual bits for
+ * locks (g_bit_lock()). There are primitives for condition variables to
+ * allow synchronization of threads (#GCond). There are primitives for
+ * thread-private data - data that every thread has a private instance
+ * of (#GPrivate, #GStaticPrivate). There are facilities for one-time
+ * initialization (#GOnce, g_once_init_enter()). Last but definitely
+ * not least there are primitives to portably create and manage
+ * threads (#GThread).
+ *
+ * The threading system is initialized with g_thread_init(), which
+ * takes an optional custom thread implementation or %NULL for the
+ * default implementation. If you want to call g_thread_init() with a
+ * non-%NULL argument this must be done before executing any other GLib
+ * functions (except g_mem_set_vtable()). This is a requirement even if
+ * no threads are in fact ever created by the process.
+ *
+ * Calling g_thread_init() with a %NULL argument is somewhat more
+ * relaxed. You may call any other glib functions in the main thread
+ * before g_thread_init() as long as g_thread_init() is not called from
+ * a glib callback, or with any locks held. However, many libraries
+ * above glib does not support late initialization of threads, so doing
+ * this should be avoided if possible.
+ *
+ * Please note that since version 2.24 the GObject initialization
+ * function g_type_init() initializes threads (with a %NULL argument),
+ * so most applications, including those using Gtk+ will run with
+ * threads enabled. If you want a special thread implementation, make
+ * sure you call g_thread_init() before g_type_init() is called.
+ *
+ * After calling g_thread_init(), GLib is completely thread safe (all
+ * global data is automatically locked), but individual data structure
+ * instances are not automatically locked for performance reasons. So,
+ * for example you must coordinate accesses to the same #GHashTable
+ * from multiple threads. The two notable exceptions from this rule
+ * are #GMainLoop and #GAsyncQueue, which <emphasis>are</emphasis>
+ * threadsafe and need no further application-level locking to be
+ * accessed from multiple threads.
+ *
+ * To help debugging problems in multithreaded applications, GLib
+ * supports error-checking mutexes that will give you helpful error
+ * messages on common problems. To use error-checking mutexes, define
+ * the symbol #G_ERRORCHECK_MUTEXES when compiling the application.
+ **/
+
+/**
+ * G_THREADS_IMPL_POSIX:
+ *
+ * This macro is defined if POSIX style threads are used.
+ **/
+
+/**
+ * G_THREADS_ENABLED:
+ *
+ * This macro is defined if GLib was compiled with thread support. This
+ * does not necessarily mean that there is a thread implementation
+ * available, but it does mean that the infrastructure is in place and
+ * that once you provide a thread implementation to g_thread_init(),
+ * GLib will be multi-thread safe. If #G_THREADS_ENABLED is not
+ * defined, then Glib is not, and cannot be, multi-thread safe.
+ **/
+
+/**
+ * G_THREADS_IMPL_NONE:
+ *
+ * This macro is defined if no thread implementation is used. You can,
+ * however, provide one to g_thread_init() to make GLib multi-thread
+ * safe.
+ **/
+
+/* G_LOCK Documentation {{{1 ---------------------------------------------- */
+
+/* IMPLEMENTATION NOTE:
+ *
+ * G_LOCK_DEFINE and friends are convenience macros defined in
+ * gthread.h. Their documentation lives here.
+ */
+
+/**
+ * G_LOCK_DEFINE:
+ * @name: the name of the lock.
+ *
+ * The %G_LOCK_* macros provide a convenient interface to #GStaticMutex
+ * with the advantage that they will expand to nothing in programs
+ * compiled against a thread-disabled GLib, saving code and memory
+ * there. #G_LOCK_DEFINE defines a lock. It can appear anywhere
+ * variable definitions may appear in programs, i.e. in the first block
+ * of a function or outside of functions. The @name parameter will be
+ * mangled to get the name of the #GStaticMutex. This means that you
+ * can use names of existing variables as the parameter - e.g. the name
+ * of the variable you intent to protect with the lock. Look at our
+ * <function>give_me_next_number()</function> example using the
+ * %G_LOCK_* macros:
+ *
+ * <example>
+ * <title>Using the %G_LOCK_* convenience macros</title>
+ * <programlisting>
+ * G_LOCK_DEFINE (current_number);
+ *
+ * int
+ * give_me_next_number (void)
+ * {
+ * static int current_number = 0;
+ * int ret_val;
+ *
+ * G_LOCK (current_number);
+ * ret_val = current_number = calc_next_number (current_number);
+ * G_UNLOCK (current_number);
+ *
+ * return ret_val;
+ * }
+ * </programlisting>
+ * </example>
+ **/
+
+/**
+ * G_LOCK_DEFINE_STATIC:
+ * @name: the name of the lock.
+ *
+ * This works like #G_LOCK_DEFINE, but it creates a static object.
+ **/
+
+/**
+ * G_LOCK_EXTERN:
+ * @name: the name of the lock.
+ *
+ * This declares a lock, that is defined with #G_LOCK_DEFINE in another
+ * module.
+ **/
+
+/**
+ * G_LOCK:
+ * @name: the name of the lock.
+ *
+ * Works like g_mutex_lock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ **/
+
+/**
+ * G_TRYLOCK:
+ * @name: the name of the lock.
+ * @Returns: %TRUE, if the lock could be locked.
+ *
+ * Works like g_mutex_trylock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ **/
+
+/**
+ * G_UNLOCK:
+ * @name: the name of the lock.
+ *
+ * Works like g_mutex_unlock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ **/
+
+/* GThreadError {{{1 ------------------------------------------------------- */
+/**
+ * GThreadError:
+ * @G_THREAD_ERROR_AGAIN: a thread couldn't be created due to resource
+ * shortage. Try again later.
+ *
+ * Possible errors of thread related functions.
+ **/
+
+/**
+ * G_THREAD_ERROR:
+ *
+ * The error domain of the GLib thread subsystem.
+ **/
+GQuark
g_thread_error_quark (void)
{
- static GQuark quark;
- if (!quark)
- quark = g_quark_from_static_string ("g_thread_error");
- return quark;
+ return g_quark_from_static_string ("g_thread_error");
}
-/* Keep this in sync with GRealThread in gmain.c! */
+/* Miscellaneous Structures {{{1 ------------------------------------------ */
typedef struct _GRealThread GRealThread;
struct _GRealThread
{
GThread thread;
- gpointer private_data;
+ /* Bit 0 protects private_data. To avoid deadlocks, do not block while
+ * holding this (particularly on the g_thread lock). */
+ volatile gint private_data_lock;
+ GArray *private_data;
+ GRealThread *next;
gpointer retval;
GSystemThread system_thread;
};
+#define LOCK_PRIVATE_DATA(self) g_bit_lock (&(self)->private_data_lock, 0)
+#define UNLOCK_PRIVATE_DATA(self) g_bit_unlock (&(self)->private_data_lock, 0)
+
typedef struct _GStaticPrivateNode GStaticPrivateNode;
struct _GStaticPrivateNode
{
GDestroyNotify destroy;
};
-static void g_thread_cleanup (gpointer data);
-static void g_thread_fail (void);
+static void g_thread_cleanup (gpointer data);
+static void g_thread_fail (void);
+static guint64 gettime (void);
+
+guint64 (*g_thread_gettime) (void) = gettime;
-/* Global variables */
+/* Global Variables {{{1 -------------------------------------------------- */
static GSystemThread zero_thread; /* This is initialized to all zero */
gboolean g_thread_use_default_impl = TRUE;
+
+/**
+ * g_thread_supported:
+ * @Returns: %TRUE, if the thread system is initialized.
+ *
+ * This function returns %TRUE if the thread system is initialized, and
+ * %FALSE if it is not.
+ *
+ * <note><para>This function is actually a macro. Apart from taking the
+ * address of it you can however use it as if it was a
+ * function.</para></note>
+ **/
+
+/* IMPLEMENTATION NOTE:
+ *
+ * g_thread_supported() is just returns g_threads_got_initialized
+ */
gboolean g_threads_got_initialized = FALSE;
+
+/* Thread Implementation Virtual Function Table {{{1 ---------------------- */
+/* Virtual Function Table Documentation {{{2 ------------------------------ */
+/**
+ * GThreadFunctions:
+ * @mutex_new: virtual function pointer for g_mutex_new()
+ * @mutex_lock: virtual function pointer for g_mutex_lock()
+ * @mutex_trylock: virtual function pointer for g_mutex_trylock()
+ * @mutex_unlock: virtual function pointer for g_mutex_unlock()
+ * @mutex_free: virtual function pointer for g_mutex_free()
+ * @cond_new: virtual function pointer for g_cond_new()
+ * @cond_signal: virtual function pointer for g_cond_signal()
+ * @cond_broadcast: virtual function pointer for g_cond_broadcast()
+ * @cond_wait: virtual function pointer for g_cond_wait()
+ * @cond_timed_wait: virtual function pointer for g_cond_timed_wait()
+ * @cond_free: virtual function pointer for g_cond_free()
+ * @private_new: virtual function pointer for g_private_new()
+ * @private_get: virtual function pointer for g_private_get()
+ * @private_set: virtual function pointer for g_private_set()
+ * @thread_create: virtual function pointer for g_thread_create()
+ * @thread_yield: virtual function pointer for g_thread_yield()
+ * @thread_join: virtual function pointer for g_thread_join()
+ * @thread_exit: virtual function pointer for g_thread_exit()
+ * @thread_set_priority: virtual function pointer for
+ * g_thread_set_priority()
+ * @thread_self: virtual function pointer for g_thread_self()
+ * @thread_equal: used internally by recursive mutex locks and by some
+ * assertion checks
+ *
+ * This function table is used by g_thread_init() to initialize the
+ * thread system. The functions in the table are directly used by their
+ * g_* prepended counterparts (described in this document). For
+ * example, if you call g_mutex_new() then mutex_new() from the table
+ * provided to g_thread_init() will be called.
+ *
+ * <note><para>Do not use this struct unless you know what you are
+ * doing.</para></note>
+ **/
+
+/* IMPLEMENTATION NOTE:
+ *
+ * g_thread_functions_for_glib_use is a global symbol that gets used by
+ * most of the "primative" threading calls. g_mutex_lock(), for
+ * example, is just a macro that calls the appropriate virtual function
+ * out of this table.
+ *
+ * For that reason, all of those macros are documented here.
+ */
GThreadFunctions g_thread_functions_for_glib_use = {
- (GMutex*(*)())g_thread_fail, /* mutex_new */
- NULL, /* mutex_lock */
- NULL, /* mutex_trylock */
- NULL, /* mutex_unlock */
- NULL, /* mutex_free */
- (GCond*(*)())g_thread_fail, /* cond_new */
- NULL, /* cond_signal */
- NULL, /* cond_broadcast */
- NULL, /* cond_wait */
- NULL, /* cond_timed_wait */
- NULL, /* cond_free */
- (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
- NULL, /* private_get */
- NULL, /* private_set */
- (void(*)(GThreadFunc, gpointer, gulong,
- gboolean, gboolean, GThreadPriority,
- gpointer, GError**))g_thread_fail, /* thread_create */
- NULL, /* thread_yield */
+/* GMutex Virtual Functions {{{2 ------------------------------------------ */
+
+/**
+ * GMutex:
+ *
+ * The #GMutex struct is an opaque data structure to represent a mutex
+ * (mutual exclusion). It can be used to protect data against shared
+ * access. Take for example the following function:
+ *
+ * <example>
+ * <title>A function which will not work in a threaded environment</title>
+ * <programlisting>
+ * int
+ * give_me_next_number (void)
+ * {
+ * static int current_number = 0;
+ *
+ * /<!-- -->* now do a very complicated calculation to calculate the new
+ * * number, this might for example be a random number generator
+ * *<!-- -->/
+ * current_number = calc_next_number (current_number);
+ *
+ * return current_number;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * It is easy to see that this won't work in a multi-threaded
+ * application. There current_number must be protected against shared
+ * access. A first naive implementation would be:
+ *
+ * <example>
+ * <title>The wrong way to write a thread-safe function</title>
+ * <programlisting>
+ * int
+ * give_me_next_number (void)
+ * {
+ * static int current_number = 0;
+ * int ret_val;
+ * static GMutex * mutex = NULL;
+ *
+ * if (!mutex) mutex = g_mutex_new (<!-- -->);
+ *
+ * g_mutex_lock (mutex);
+ * ret_val = current_number = calc_next_number (current_number);
+ * g_mutex_unlock (mutex);
+ *
+ * return ret_val;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * This looks like it would work, but there is a race condition while
+ * constructing the mutex and this code cannot work reliable. Please do
+ * not use such constructs in your own programs! One working solution
+ * is:
+ *
+ * <example>
+ * <title>A correct thread-safe function</title>
+ * <programlisting>
+ * static GMutex *give_me_next_number_mutex = NULL;
+ *
+ * /<!-- -->* this function must be called before any call to
+ * * give_me_next_number(<!-- -->)
+ * *
+ * * it must be called exactly once.
+ * *<!-- -->/
+ * void
+ * init_give_me_next_number (void)
+ * {
+ * g_assert (give_me_next_number_mutex == NULL);
+ * give_me_next_number_mutex = g_mutex_new (<!-- -->);
+ * }
+ *
+ * int
+ * give_me_next_number (void)
+ * {
+ * static int current_number = 0;
+ * int ret_val;
+ *
+ * g_mutex_lock (give_me_next_number_mutex);
+ * ret_val = current_number = calc_next_number (current_number);
+ * g_mutex_unlock (give_me_next_number_mutex);
+ *
+ * return ret_val;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * #GStaticMutex provides a simpler and safer way of doing this.
+ *
+ * If you want to use a mutex, and your code should also work without
+ * calling g_thread_init() first, then you cannot use a #GMutex, as
+ * g_mutex_new() requires that the thread system be initialized. Use a
+ * #GStaticMutex instead.
+ *
+ * A #GMutex should only be accessed via the following functions.
+ *
+ * <note><para>All of the <function>g_mutex_*</function> functions are
+ * actually macros. Apart from taking their addresses, you can however
+ * use them as if they were functions.</para></note>
+ **/
+
+/**
+ * g_mutex_new:
+ * @Returns: a new #GMutex.
+ *
+ * Creates a new #GMutex.
+ *
+ * <note><para>This function will abort if g_thread_init() has not been
+ * called yet.</para></note>
+ **/
+ (GMutex*(*)())g_thread_fail,
+
+/**
+ * g_mutex_lock:
+ * @mutex: a #GMutex.
+ *
+ * Locks @mutex. If @mutex is already locked by another thread, the
+ * current thread will block until @mutex is unlocked by the other
+ * thread.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will do nothing.
+ *
+ * <note><para>#GMutex is neither guaranteed to be recursive nor to be
+ * non-recursive, i.e. a thread could deadlock while calling
+ * g_mutex_lock(), if it already has locked @mutex. Use
+ * #GStaticRecMutex, if you need recursive mutexes.</para></note>
+ **/
+ NULL,
+
+/**
+ * g_mutex_trylock:
+ * @mutex: a #GMutex.
+ * @Returns: %TRUE, if @mutex could be locked.
+ *
+ * Tries to lock @mutex. If @mutex is already locked by another thread,
+ * it immediately returns %FALSE. Otherwise it locks @mutex and returns
+ * %TRUE.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will immediately return %TRUE.
+ *
+ * <note><para>#GMutex is neither guaranteed to be recursive nor to be
+ * non-recursive, i.e. the return value of g_mutex_trylock() could be
+ * both %FALSE or %TRUE, if the current thread already has locked
+ * @mutex. Use #GStaticRecMutex, if you need recursive
+ * mutexes.</para></note>
+ **/
+ NULL,
+
+/**
+ * g_mutex_unlock:
+ * @mutex: a #GMutex.
+ *
+ * Unlocks @mutex. If another thread is blocked in a g_mutex_lock()
+ * call for @mutex, it will be woken and can lock @mutex itself.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will do nothing.
+ **/
+ NULL,
+
+/**
+ * g_mutex_free:
+ * @mutex: a #GMutex.
+ *
+ * Destroys @mutex.
+ *
+ * <note><para>Calling g_mutex_free() on a locked mutex may result in
+ * undefined behaviour.</para></note>
+ **/
+ NULL,
+
+/* GCond Virtual Functions {{{2 ------------------------------------------ */
+
+/**
+ * GCond:
+ *
+ * The #GCond struct is an opaque data structure that represents a
+ * condition. Threads can block on a #GCond if they find a certain
+ * condition to be false. If other threads change the state of this
+ * condition they signal the #GCond, and that causes the waiting
+ * threads to be woken up.
+ *
+ * <example>
+ * <title>
+ * Using GCond to block a thread until a condition is satisfied
+ * </title>
+ * <programlisting>
+ * GCond* data_cond = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/
+ * GMutex* data_mutex = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/
+ * gpointer current_data = NULL;
+ *
+ * void
+ * push_data (gpointer data)
+ * {
+ * g_mutex_lock (data_mutex);
+ * current_data = data;
+ * g_cond_signal (data_cond);
+ * g_mutex_unlock (data_mutex);
+ * }
+ *
+ * gpointer
+ * pop_data (void)
+ * {
+ * gpointer data;
+ *
+ * g_mutex_lock (data_mutex);
+ * while (!current_data)
+ * g_cond_wait (data_cond, data_mutex);
+ * data = current_data;
+ * current_data = NULL;
+ * g_mutex_unlock (data_mutex);
+ *
+ * return data;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * Whenever a thread calls <function>pop_data()</function> now, it will
+ * wait until current_data is non-%NULL, i.e. until some other thread
+ * has called <function>push_data()</function>.
+ *
+ * <note><para>It is important to use the g_cond_wait() and
+ * g_cond_timed_wait() functions only inside a loop which checks for the
+ * condition to be true. It is not guaranteed that the waiting thread
+ * will find the condition fulfilled after it wakes up, even if the
+ * signaling thread left the condition in that state: another thread may
+ * have altered the condition before the waiting thread got the chance
+ * to be woken up, even if the condition itself is protected by a
+ * #GMutex, like above.</para></note>
+ *
+ * A #GCond should only be accessed via the following functions.
+ *
+ * <note><para>All of the <function>g_cond_*</function> functions are
+ * actually macros. Apart from taking their addresses, you can however
+ * use them as if they were functions.</para></note>
+ **/
+
+/**
+ * g_cond_new:
+ * @Returns: a new #GCond.
+ *
+ * Creates a new #GCond. This function will abort, if g_thread_init()
+ * has not been called yet.
+ **/
+ (GCond*(*)())g_thread_fail,
+
+/**
+ * g_cond_signal:
+ * @cond: a #GCond.
+ *
+ * If threads are waiting for @cond, exactly one of them is woken up.
+ * It is good practice to hold the same lock as the waiting thread
+ * while calling this function, though not required.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will do nothing.
+ **/
+ NULL,
+
+/**
+ * g_cond_broadcast:
+ * @cond: a #GCond.
+ *
+ * If threads are waiting for @cond, all of them are woken up. It is
+ * good practice to lock the same mutex as the waiting threads, while
+ * calling this function, though not required.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will do nothing.
+ **/
+ NULL,
+
+/**
+ * g_cond_wait:
+ * @cond: a #GCond.
+ * @mutex: a #GMutex, that is currently locked.
+ *
+ * Waits until this thread is woken up on @cond. The @mutex is unlocked
+ * before falling asleep and locked again before resuming.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will immediately return.
+ **/
+ NULL,
+
+/**
+ * g_cond_timed_wait:
+ * @cond: a #GCond.
+ * @mutex: a #GMutex that is currently locked.
+ * @abs_time: a #GTimeVal, determining the final time.
+ * @Returns: %TRUE if @cond was signalled, or %FALSE on timeout.
+ *
+ * Waits until this thread is woken up on @cond, but not longer than
+ * until the time specified by @abs_time. The @mutex is unlocked before
+ * falling asleep and locked again before resuming.
+ *
+ * If @abs_time is %NULL, g_cond_timed_wait() acts like g_cond_wait().
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will immediately return %TRUE.
+ *
+ * To easily calculate @abs_time a combination of g_get_current_time()
+ * and g_time_val_add() can be used.
+ **/
+ NULL,
+
+/**
+ * g_cond_free:
+ * @cond: a #GCond.
+ *
+ * Destroys the #GCond.
+ **/
+ NULL,
+
+/* GPrivate Virtual Functions {{{2 --------------------------------------- */
+
+/**
+ * GPrivate:
+ *
+ * The #GPrivate struct is an opaque data structure to represent a
+ * thread private data key. Threads can thereby obtain and set a
+ * pointer which is private to the current thread. Take our
+ * <function>give_me_next_number(<!-- -->)</function> example from
+ * above. Suppose we don't want <literal>current_number</literal> to be
+ * shared between the threads, but instead to be private to each thread.
+ * This can be done as follows:
+ *
+ * <example>
+ * <title>Using GPrivate for per-thread data</title>
+ * <programlisting>
+ * GPrivate* current_number_key = NULL; /<!-- -->* Must be initialized somewhere
+ * with g_private_new (g_free); *<!-- -->/
+ *
+ * int
+ * give_me_next_number (void)
+ * {
+ * int *current_number = g_private_get (current_number_key);
+ *
+ * if (!current_number)
+ * {
+ * current_number = g_new (int, 1);
+ * *current_number = 0;
+ * g_private_set (current_number_key, current_number);
+ * }
+ *
+ * *current_number = calc_next_number (*current_number);
+ *
+ * return *current_number;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * Here the pointer belonging to the key
+ * <literal>current_number_key</literal> is read. If it is %NULL, it has
+ * not been set yet. Then get memory for an integer value, assign this
+ * memory to the pointer and write the pointer back. Now we have an
+ * integer value that is private to the current thread.
+ *
+ * The #GPrivate struct should only be accessed via the following
+ * functions.
+ *
+ * <note><para>All of the <function>g_private_*</function> functions are
+ * actually macros. Apart from taking their addresses, you can however
+ * use them as if they were functions.</para></note>
+ **/
+
+/**
+ * g_private_new:
+ * @destructor: a function to destroy the data keyed to #GPrivate when
+ * a thread ends.
+ * @Returns: a new #GPrivate.
+ *
+ * Creates a new #GPrivate. If @destructor is non-%NULL, it is a
+ * pointer to a destructor function. Whenever a thread ends and the
+ * corresponding pointer keyed to this instance of #GPrivate is
+ * non-%NULL, the destructor is called with this pointer as the
+ * argument.
+ *
+ * <note><para>@destructor is used quite differently from @notify in
+ * g_static_private_set().</para></note>
+ *
+ * <note><para>A #GPrivate cannot be freed. Reuse it instead, if you
+ * can, to avoid shortage, or use #GStaticPrivate.</para></note>
+ *
+ * <note><para>This function will abort if g_thread_init() has not been
+ * called yet.</para></note>
+ **/
+ (GPrivate*(*)(GDestroyNotify))g_thread_fail,
+
+/**
+ * g_private_get:
+ * @private_key: a #GPrivate.
+ * @Returns: the corresponding pointer.
+ *
+ * Returns the pointer keyed to @private_key for the current thread. If
+ * g_private_set() hasn't been called for the current @private_key and
+ * thread yet, this pointer will be %NULL.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will return the value of @private_key
+ * casted to #gpointer. Note however, that private data set
+ * <emphasis>before</emphasis> g_thread_init() will
+ * <emphasis>not</emphasis> be retained <emphasis>after</emphasis> the
+ * call. Instead, %NULL will be returned in all threads directly after
+ * g_thread_init(), regardless of any g_private_set() calls issued
+ * before threading system intialization.
+ **/
+ NULL,
+
+/**
+ * g_private_set:
+ * @private_key: a #GPrivate.
+ * @data: the new pointer.
+ *
+ * Sets the pointer keyed to @private_key for the current thread.
+ *
+ * This function can be used even if g_thread_init() has not yet been
+ * called, and, in that case, will set @private_key to @data casted to
+ * #GPrivate*. See g_private_get() for resulting caveats.
+ **/
+ NULL,
+
+/* GThread Virtual Functions {{{2 ---------------------------------------- */
+/**
+ * GThread:
+ *
+ * The #GThread struct represents a running thread. It has three public
+ * read-only members, but the underlying struct is bigger, so you must
+ * not copy this struct.
+ *
+ * <note><para>Resources for a joinable thread are not fully released
+ * until g_thread_join() is called for that thread.</para></note>
+ **/
+
+/**
+ * GThreadFunc:
+ * @data: data passed to the thread.
+ * @Returns: the return value of the thread, which will be returned by
+ * g_thread_join().
+ *
+ * Specifies the type of the @func functions passed to
+ * g_thread_create() or g_thread_create_full().
+ **/
+
+/**
+ * GThreadPriority:
+ * @G_THREAD_PRIORITY_LOW: a priority lower than normal
+ * @G_THREAD_PRIORITY_NORMAL: the default priority
+ * @G_THREAD_PRIORITY_HIGH: a priority higher than normal
+ * @G_THREAD_PRIORITY_URGENT: the highest priority
+ *
+ * Specifies the priority of a thread.
+ *
+ * <note><para>It is not guaranteed that threads with different priorities
+ * really behave accordingly. On some systems (e.g. Linux) there are no
+ * thread priorities. On other systems (e.g. Solaris) there doesn't
+ * seem to be different scheduling for different priorities. All in all
+ * try to avoid being dependent on priorities.</para></note>
+ **/
+
+/**
+ * g_thread_create:
+ * @func: a function to execute in the new thread.
+ * @data: an argument to supply to the new thread.
+ * @joinable: should this thread be joinable?
+ * @error: return location for error.
+ * @Returns: the new #GThread on success.
+ *
+ * This function creates a new thread with the default priority.
+ *
+ * If @joinable is %TRUE, you can wait for this threads termination
+ * calling g_thread_join(). Otherwise the thread will just disappear
+ * when it terminates.
+ *
+ * The new thread executes the function @func with the argument @data.
+ * If the thread was created successfully, it is returned.
+ *
+ * @error can be %NULL to ignore errors, or non-%NULL to report errors.
+ * The error is set, if and only if the function returns %NULL.
+ **/
+ (void(*)(GThreadFunc, gpointer, gulong,
+ gboolean, gboolean, GThreadPriority,
+ gpointer, GError**))g_thread_fail,
+
+/**
+ * g_thread_yield:
+ *
+ * Gives way to other threads waiting to be scheduled.
+ *
+ * This function is often used as a method to make busy wait less evil.
+ * But in most cases you will encounter, there are better methods to do
+ * that. So in general you shouldn't use this function.
+ **/
+ NULL,
+
NULL, /* thread_join */
NULL, /* thread_exit */
NULL, /* thread_set_priority */
- NULL /* thread_self */
-};
+ NULL, /* thread_self */
+ NULL /* thread_equal */
+};
-/* Local data */
+/* Local Data {{{1 -------------------------------------------------------- */
static GMutex *g_once_mutex = NULL;
static GCond *g_once_cond = NULL;
static GPrivate *g_thread_specific_private = NULL;
-static GSList *g_thread_all_threads = NULL;
-static GSList *g_thread_free_indeces = NULL;
+static GRealThread *g_thread_all_threads = NULL;
+static GSList *g_thread_free_indices = NULL;
+static GSList* g_once_init_list = NULL;
G_LOCK_DEFINE_STATIC (g_thread);
+/* Initialisation {{{1 ---------------------------------------------------- */
+
#ifdef G_THREADS_ENABLED
+/**
+ * g_thread_init:
+ * @vtable: a function table of type #GThreadFunctions, that provides
+ * the entry points to the thread system to be used.
+ *
+ * If you use GLib from more than one thread, you must initialize the
+ * thread system by calling g_thread_init(). Most of the time you will
+ * only have to call <literal>g_thread_init (NULL)</literal>.
+ *
+ * <note><para>Do not call g_thread_init() with a non-%NULL parameter unless
+ * you really know what you are doing.</para></note>
+ *
+ * <note><para>g_thread_init() must not be called directly or indirectly as a
+ * callback from GLib. Also no mutexes may be currently locked while
+ * calling g_thread_init().</para></note>
+ *
+ * <note><para>g_thread_init() changes the way in which #GTimer measures
+ * elapsed time. As a consequence, timers that are running while
+ * g_thread_init() is called may report unreliable times.</para></note>
+ *
+ * Calling g_thread_init() multiple times is allowed (since version
+ * 2.24), but nothing happens except for the first call. If the
+ * argument is non-%NULL on such a call a warning will be printed, but
+ * otherwise the argument is ignored.
+ *
+ * If no thread system is available and @vtable is %NULL or if not all
+ * elements of @vtable are non-%NULL, then g_thread_init() will abort.
+ *
+ * <note><para>To use g_thread_init() in your program, you have to link with
+ * the libraries that the command <command>pkg-config --libs
+ * gthread-2.0</command> outputs. This is not the case for all the
+ * other thread related functions of GLib. Those can be used without
+ * having to link with the thread libraries.</para></note>
+ **/
+
/* This must be called only once, before any threads are created.
* It will only be called from g_thread_init() in -lgthread.
*/
-void
+void
g_thread_init_glib (void)
{
/* We let the main thread (the one that calls g_thread_init) inherit
*/
GRealThread* main_thread = (GRealThread*) g_thread_self ();
+ /* mutex and cond creation works without g_threads_got_initialized */
g_once_mutex = g_mutex_new ();
g_once_cond = g_cond_new ();
- _g_convert_thread_init ();
- _g_rand_thread_init ();
- _g_main_thread_init ();
- _g_mem_thread_init ();
- _g_messages_thread_init ();
- _g_atomic_thread_init ();
-#ifdef G_OS_WIN32
- _g_win32_thread_init ();
-#endif
+ /* we may only create mutex and cond in here */
+ _g_mem_thread_init_noprivate_nomessage ();
+ /* setup the basic threading system */
g_threads_got_initialized = TRUE;
-
g_thread_specific_private = g_private_new (g_thread_cleanup);
g_private_set (g_thread_specific_private, main_thread);
G_THREAD_UF (thread_self, (&main_thread->system_thread));
- _g_mem_thread_private_init ();
- _g_messages_thread_private_init ();
+ /* complete memory system initialization, g_private_*() works now */
+ _g_slice_thread_init_nomessage ();
+
+ /* accomplish log system initialization to enable messaging */
+ _g_messages_thread_init_nomessage ();
+ /* we may run full-fledged initializers from here */
+ _g_convert_thread_init ();
+ _g_rand_thread_init ();
+ _g_main_thread_init ();
+ _g_utils_thread_init ();
+ _g_futex_thread_init ();
+#ifdef G_OS_WIN32
+ _g_win32_thread_init ();
+#endif
}
#endif /* G_THREADS_ENABLED */
-gpointer
-g_once_impl (GOnce *once,
- GThreadFunc func,
+/* The following sections implement: GOnce, GStaticMutex, GStaticRecMutex,
+ * GStaticPrivate,
+ **/
+
+/* GOnce {{{1 ------------------------------------------------------------- */
+
+/**
+ * GOnce:
+ * @status: the status of the #GOnce
+ * @retval: the value returned by the call to the function, if @status
+ * is %G_ONCE_STATUS_READY
+ *
+ * A #GOnce struct controls a one-time initialization function. Any
+ * one-time initialization function must have its own unique #GOnce
+ * struct.
+ *
+ * Since: 2.4
+ **/
+
+/**
+ * G_ONCE_INIT:
+ *
+ * A #GOnce must be initialized with this macro before it can be used.
+ *
+ * <informalexample>
+ * <programlisting>
+ * GOnce my_once = G_ONCE_INIT;
+ * </programlisting>
+ * </informalexample>
+ *
+ * Since: 2.4
+ **/
+
+/**
+ * GOnceStatus:
+ * @G_ONCE_STATUS_NOTCALLED: the function has not been called yet.
+ * @G_ONCE_STATUS_PROGRESS: the function call is currently in progress.
+ * @G_ONCE_STATUS_READY: the function has been called.
+ *
+ * The possible statuses of a one-time initialization function
+ * controlled by a #GOnce struct.
+ *
+ * Since: 2.4
+ **/
+
+/**
+ * g_once:
+ * @once: a #GOnce structure
+ * @func: the #GThreadFunc function associated to @once. This function
+ * is called only once, regardless of the number of times it and
+ * its associated #GOnce struct are passed to g_once().
+ * @arg: data to be passed to @func
+ *
+ * The first call to this routine by a process with a given #GOnce
+ * struct calls @func with the given argument. Thereafter, subsequent
+ * calls to g_once() with the same #GOnce struct do not call @func
+ * again, but return the stored result of the first call. On return
+ * from g_once(), the status of @once will be %G_ONCE_STATUS_READY.
+ *
+ * For example, a mutex or a thread-specific data key must be created
+ * exactly once. In a threaded environment, calling g_once() ensures
+ * that the initialization is serialized across multiple threads.
+ *
+ * <note><para>Calling g_once() recursively on the same #GOnce struct in
+ * @func will lead to a deadlock.</para></note>
+ *
+ * <informalexample>
+ * <programlisting>
+ * gpointer
+ * get_debug_flags (void)
+ * {
+ * static GOnce my_once = G_ONCE_INIT;
+ *
+ * g_once (&my_once, parse_debug_flags, NULL);
+ *
+ * return my_once.retval;
+ * }
+ * </programlisting>
+ * </informalexample>
+ *
+ * Since: 2.4
+ **/
+gpointer
+g_once_impl (GOnce *once,
+ GThreadFunc func,
gpointer arg)
{
g_mutex_lock (g_once_mutex);
while (once->status == G_ONCE_STATUS_PROGRESS)
g_cond_wait (g_once_cond, g_once_mutex);
-
+
if (once->status != G_ONCE_STATUS_READY)
{
once->status = G_ONCE_STATUS_PROGRESS;
g_mutex_unlock (g_once_mutex);
-
+
once->retval = func (arg);
g_mutex_lock (g_once_mutex);
once->status = G_ONCE_STATUS_READY;
g_cond_broadcast (g_once_cond);
}
-
+
g_mutex_unlock (g_once_mutex);
-
+
return once->retval;
}
-void
+/**
+ * g_once_init_enter:
+ * @value_location: location of a static initializable variable
+ * containing 0.
+ * @Returns: %TRUE if the initialization section should be entered,
+ * %FALSE and blocks otherwise
+ *
+ * Function to be called when starting a critical initialization
+ * section. The argument @value_location must point to a static
+ * 0-initialized variable that will be set to a value other than 0 at
+ * the end of the initialization section. In combination with
+ * g_once_init_leave() and the unique address @value_location, it can
+ * be ensured that an initialization section will be executed only once
+ * during a program's life time, and that concurrent threads are
+ * blocked until initialization completed. To be used in constructs
+ * like this:
+ *
+ * <informalexample>
+ * <programlisting>
+ * static gsize initialization_value = 0;
+ *
+ * if (g_once_init_enter (&initialization_value))
+ * {
+ * gsize setup_value = 42; /<!-- -->* initialization code here *<!-- -->/
+ *
+ * g_once_init_leave (&initialization_value, setup_value);
+ * }
+ *
+ * /<!-- -->* use initialization_value here *<!-- -->/
+ * </programlisting>
+ * </informalexample>
+ *
+ * Since: 2.14
+ **/
+gboolean
+g_once_init_enter_impl (volatile gsize *value_location)
+{
+ gboolean need_init = FALSE;
+ g_mutex_lock (g_once_mutex);
+ if (g_atomic_pointer_get (value_location) == NULL)
+ {
+ if (!g_slist_find (g_once_init_list, (void*) value_location))
+ {
+ need_init = TRUE;
+ g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location);
+ }
+ else
+ do
+ g_cond_wait (g_once_cond, g_once_mutex);
+ while (g_slist_find (g_once_init_list, (void*) value_location));
+ }
+ g_mutex_unlock (g_once_mutex);
+ return need_init;
+}
+
+/**
+ * g_once_init_leave:
+ * @value_location: location of a static initializable variable
+ * containing 0.
+ * @initialization_value: new non-0 value for *@value_location.
+ *
+ * Counterpart to g_once_init_enter(). Expects a location of a static
+ * 0-initialized initialization variable, and an initialization value
+ * other than 0. Sets the variable to the initialization value, and
+ * releases concurrent threads blocking in g_once_init_enter() on this
+ * initialization variable.
+ *
+ * Since: 2.14
+ **/
+void
+g_once_init_leave (volatile gsize *value_location,
+ gsize initialization_value)
+{
+ g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
+ g_return_if_fail (initialization_value != 0);
+ g_return_if_fail (g_once_init_list != NULL);
+
+ g_atomic_pointer_set (value_location, initialization_value);
+ g_mutex_lock (g_once_mutex);
+ g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location);
+ g_cond_broadcast (g_once_cond);
+ g_mutex_unlock (g_once_mutex);
+}
+
+/* GStaticMutex {{{1 ------------------------------------------------------ */
+
+/**
+ * GStaticMutex:
+ *
+ * A #GStaticMutex works like a #GMutex, but it has one significant
+ * advantage. It doesn't need to be created at run-time like a #GMutex,
+ * but can be defined at compile-time. Here is a shorter, easier and
+ * safer version of our <function>give_me_next_number()</function>
+ * example:
+ *
+ * <example>
+ * <title>
+ * Using <structname>GStaticMutex</structname>
+ * to simplify thread-safe programming
+ * </title>
+ * <programlisting>
+ * int
+ * give_me_next_number (void)
+ * {
+ * static int current_number = 0;
+ * int ret_val;
+ * static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
+ *
+ * g_static_mutex_lock (&mutex);
+ * ret_val = current_number = calc_next_number (current_number);
+ * g_static_mutex_unlock (&mutex);
+ *
+ * return ret_val;
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * Sometimes you would like to dynamically create a mutex. If you don't
+ * want to require prior calling to g_thread_init(), because your code
+ * should also be usable in non-threaded programs, you are not able to
+ * use g_mutex_new() and thus #GMutex, as that requires a prior call to
+ * g_thread_init(). In theses cases you can also use a #GStaticMutex.
+ * It must be initialized with g_static_mutex_init() before using it
+ * and freed with with g_static_mutex_free() when not needed anymore to
+ * free up any allocated resources.
+ *
+ * Even though #GStaticMutex is not opaque, it should only be used with
+ * the following functions, as it is defined differently on different
+ * platforms.
+ *
+ * All of the <function>g_static_mutex_*</function> functions apart
+ * from <function>g_static_mutex_get_mutex</function> can also be used
+ * even if g_thread_init() has not yet been called. Then they do
+ * nothing, apart from <function>g_static_mutex_trylock</function>,
+ * which does nothing but returning %TRUE.
+ *
+ * <note><para>All of the <function>g_static_mutex_*</function>
+ * functions are actually macros. Apart from taking their addresses, you
+ * can however use them as if they were functions.</para></note>
+ **/
+
+/**
+ * G_STATIC_MUTEX_INIT:
+ *
+ * A #GStaticMutex must be initialized with this macro, before it can
+ * be used. This macro can used be to initialize a variable, but it
+ * cannot be assigned to a variable. In that case you have to use
+ * g_static_mutex_init().
+ *
+ * <informalexample>
+ * <programlisting>
+ * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
+ * </programlisting>
+ * </informalexample>
+ **/
+
+/**
+ * g_static_mutex_init:
+ * @mutex: a #GStaticMutex to be initialized.
+ *
+ * Initializes @mutex. Alternatively you can initialize it with
+ * #G_STATIC_MUTEX_INIT.
+ **/
+void
g_static_mutex_init (GStaticMutex *mutex)
{
- static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
+ static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
g_return_if_fail (mutex);
*mutex = init_mutex;
}
+/* IMPLEMENTATION NOTE:
+ *
+ * On some platforms a GStaticMutex is actually a normal GMutex stored
+ * inside of a structure instead of being allocated dynamically. We can
+ * only do this for platforms on which we know, in advance, how to
+ * allocate (size) and initialise (value) that memory.
+ *
+ * On other platforms, a GStaticMutex is nothing more than a pointer to
+ * a GMutex. In that case, the first access we make to the static mutex
+ * must first allocate the normal GMutex and store it into the pointer.
+ *
+ * configure.ac writes macros into glibconfig.h to determine if
+ * g_static_mutex_get_mutex() accesses the sturcture in memory directly
+ * (on platforms where we are able to do that) or if it ends up here,
+ * where we may have to allocate the GMutex before returning it.
+ */
+
+/**
+ * g_static_mutex_get_mutex:
+ * @mutex: a #GStaticMutex.
+ * @Returns: the #GMutex corresponding to @mutex.
+ *
+ * For some operations (like g_cond_wait()) you must have a #GMutex
+ * instead of a #GStaticMutex. This function will return the
+ * corresponding #GMutex for @mutex.
+ **/
GMutex *
g_static_mutex_get_mutex_impl (GMutex** mutex)
{
+ GMutex *result;
+
if (!g_thread_supported ())
return NULL;
- g_assert (g_once_mutex);
+ result = g_atomic_pointer_get (mutex);
- g_mutex_lock (g_once_mutex);
-
- if (!(*mutex))
+ if (!result)
{
- GMutex *new_mutex = g_mutex_new ();
-
- /* The following is a memory barrier to avoid the write
- * to *new_mutex being reordered to after writing *mutex */
- g_mutex_lock (new_mutex);
- g_mutex_unlock (new_mutex);
-
- *mutex = new_mutex;
+ g_assert (g_once_mutex);
+
+ g_mutex_lock (g_once_mutex);
+
+ result = *mutex;
+ if (!result)
+ {
+ result = g_mutex_new ();
+ g_atomic_pointer_set (mutex, result);
+ }
+
+ g_mutex_unlock (g_once_mutex);
}
- g_mutex_unlock (g_once_mutex);
-
- return *mutex;
+ return result;
}
+/* IMPLEMENTATION NOTE:
+ *
+ * g_static_mutex_lock(), g_static_mutex_trylock() and
+ * g_static_mutex_unlock() are all preprocessor macros that wrap the
+ * corresponding g_mutex_*() function around a call to
+ * g_static_mutex_get_mutex().
+ */
+
+/**
+ * g_static_mutex_lock:
+ * @mutex: a #GStaticMutex.
+ *
+ * Works like g_mutex_lock(), but for a #GStaticMutex.
+ **/
+
+/**
+ * g_static_mutex_trylock:
+ * @mutex: a #GStaticMutex.
+ * @Returns: %TRUE, if the #GStaticMutex could be locked.
+ *
+ * Works like g_mutex_trylock(), but for a #GStaticMutex.
+ **/
+
+/**
+ * g_static_mutex_unlock:
+ * @mutex: a #GStaticMutex.
+ *
+ * Works like g_mutex_unlock(), but for a #GStaticMutex.
+ **/
+
+/**
+ * g_static_mutex_free:
+ * @mutex: a #GStaticMutex to be freed.
+ *
+ * Releases all resources allocated to @mutex.
+ *
+ * You don't have to call this functions for a #GStaticMutex with an
+ * unbounded lifetime, i.e. objects declared 'static', but if you have
+ * a #GStaticMutex as a member of a structure and the structure is
+ * freed, you should also free the #GStaticMutex.
+ *
+ * <note><para>Calling g_static_mutex_free() on a locked mutex may
+ * result in undefined behaviour.</para></note>
+ **/
void
g_static_mutex_free (GStaticMutex* mutex)
{
GMutex **runtime_mutex;
-
+
g_return_if_fail (mutex);
/* The runtime_mutex is the first (or only) member of GStaticMutex,
- * see both versions (of glibconfig.h) in configure.in */
+ * see both versions (of glibconfig.h) in configure.ac. Note, that
+ * this variable is NULL, if g_thread_init() hasn't been called or
+ * if we're using the default thread implementation and it provides
+ * static mutexes. */
runtime_mutex = ((GMutex**)mutex);
-
+
if (*runtime_mutex)
g_mutex_free (*runtime_mutex);
*runtime_mutex = NULL;
}
-void
+/* ------------------------------------------------------------------------ */
+
+/**
+ * GStaticRecMutex:
+ *
+ * A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
+ * multiple times by one thread. If you enter it n times, you have to
+ * unlock it n times again to let other threads lock it. An exception
+ * is the function g_static_rec_mutex_unlock_full(): that allows you to
+ * unlock a #GStaticRecMutex completely returning the depth, (i.e. the
+ * number of times this mutex was locked). The depth can later be used
+ * to restore the state of the #GStaticRecMutex by calling
+ * g_static_rec_mutex_lock_full().
+ *
+ * Even though #GStaticRecMutex is not opaque, it should only be used
+ * with the following functions.
+ *
+ * All of the <function>g_static_rec_mutex_*</function> functions can
+ * be used even if g_thread_init() has not been called. Then they do
+ * nothing, apart from <function>g_static_rec_mutex_trylock</function>,
+ * which does nothing but returning %TRUE.
+ **/
+
+/**
+ * G_STATIC_REC_MUTEX_INIT:
+ *
+ * A #GStaticRecMutex must be initialized with this macro before it can
+ * be used. This macro can used be to initialize a variable, but it
+ * cannot be assigned to a variable. In that case you have to use
+ * g_static_rec_mutex_init().
+ *
+ * <informalexample>
+ * <programlisting>
+ * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
+ * </programlisting>
+ </informalexample>
+ **/
+
+/**
+ * g_static_rec_mutex_init:
+ * @mutex: a #GStaticRecMutex to be initialized.
+ *
+ * A #GStaticRecMutex must be initialized with this function before it
+ * can be used. Alternatively you can initialize it with
+ * #G_STATIC_REC_MUTEX_INIT.
+ **/
+void
g_static_rec_mutex_init (GStaticRecMutex *mutex)
{
- static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
-
+ static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
+
g_return_if_fail (mutex);
*mutex = init_mutex;
}
+/**
+ * g_static_rec_mutex_lock:
+ * @mutex: a #GStaticRecMutex to lock.
+ *
+ * Locks @mutex. If @mutex is already locked by another thread, the
+ * current thread will block until @mutex is unlocked by the other
+ * thread. If @mutex is already locked by the calling thread, this
+ * functions increases the depth of @mutex and returns immediately.
+ **/
void
g_static_rec_mutex_lock (GStaticRecMutex* mutex)
{
mutex->depth = 1;
}
+/**
+ * g_static_rec_mutex_trylock:
+ * @mutex: a #GStaticRecMutex to lock.
+ * @Returns: %TRUE, if @mutex could be locked.
+ *
+ * Tries to lock @mutex. If @mutex is already locked by another thread,
+ * it immediately returns %FALSE. Otherwise it locks @mutex and returns
+ * %TRUE. If @mutex is already locked by the calling thread, this
+ * functions increases the depth of @mutex and immediately returns
+ * %TRUE.
+ **/
gboolean
g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
{
return TRUE;
}
+/**
+ * g_static_rec_mutex_unlock:
+ * @mutex: a #GStaticRecMutex to unlock.
+ *
+ * Unlocks @mutex. Another thread will be allowed to lock @mutex only
+ * when it has been unlocked as many times as it had been locked
+ * before. If @mutex is completely unlocked and another thread is
+ * blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
+ * woken and can lock @mutex itself.
+ **/
void
g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
{
return;
}
g_system_thread_assign (mutex->owner, zero_thread);
- g_static_mutex_unlock (&mutex->mutex);
+ g_static_mutex_unlock (&mutex->mutex);
}
+/**
+ * g_static_rec_mutex_lock_full:
+ * @mutex: a #GStaticRecMutex to lock.
+ * @depth: number of times this mutex has to be unlocked to be
+ * completely unlocked.
+ *
+ * Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
+ **/
void
g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
guint depth)
if (!g_thread_supported ())
return;
+ if (depth == 0)
+ return;
+
G_THREAD_UF (thread_self, (&self));
if (g_system_thread_equal (self, mutex->owner))
mutex->depth = depth;
}
-guint
+/**
+ * g_static_rec_mutex_unlock_full:
+ * @mutex: a #GStaticRecMutex to completely unlock.
+ * @Returns: number of times @mutex has been locked by the current
+ * thread.
+ *
+ * Completely unlocks @mutex. If another thread is blocked in a
+ * g_static_rec_mutex_lock() call for @mutex, it will be woken and can
+ * lock @mutex itself. This function returns the number of times that
+ * @mutex has been locked by the current thread. To restore the state
+ * before the call to g_static_rec_mutex_unlock_full() you can call
+ * g_static_rec_mutex_lock_full() with the depth returned by this
+ * function.
+ **/
+guint
g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
{
guint depth;
return depth;
}
+/**
+ * g_static_rec_mutex_free:
+ * @mutex: a #GStaticRecMutex to be freed.
+ *
+ * Releases all resources allocated to a #GStaticRecMutex.
+ *
+ * You don't have to call this functions for a #GStaticRecMutex with an
+ * unbounded lifetime, i.e. objects declared 'static', but if you have
+ * a #GStaticRecMutex as a member of a structure and the structure is
+ * freed, you should also free the #GStaticRecMutex.
+ **/
void
g_static_rec_mutex_free (GStaticRecMutex *mutex)
{
g_static_mutex_free (&mutex->mutex);
}
-void
+/* GStaticPrivate {{{1 ---------------------------------------------------- */
+
+/**
+ * GStaticPrivate:
+ *
+ * A #GStaticPrivate works almost like a #GPrivate, but it has one
+ * significant advantage. It doesn't need to be created at run-time
+ * like a #GPrivate, but can be defined at compile-time. This is
+ * similar to the difference between #GMutex and #GStaticMutex. Now
+ * look at our <function>give_me_next_number()</function> example with
+ * #GStaticPrivate:
+ *
+ * <example>
+ * <title>Using GStaticPrivate for per-thread data</title>
+ * <programlisting>
+ * int
+ * give_me_next_number (<!-- -->)
+ * {
+ * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
+ * int *current_number = g_static_private_get (&current_number_key);
+ *
+ * if (!current_number)
+ * {
+ * current_number = g_new (int,1);
+ * *current_number = 0;
+ * g_static_private_set (&current_number_key, current_number, g_free);
+ * }
+ *
+ * *current_number = calc_next_number (*current_number);
+ *
+ * return *current_number;
+ * }
+ * </programlisting>
+ * </example>
+ **/
+
+/**
+ * G_STATIC_PRIVATE_INIT:
+ *
+ * Every #GStaticPrivate must be initialized with this macro, before it
+ * can be used.
+ *
+ * <informalexample>
+ * <programlisting>
+ * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
+ * </programlisting>
+ * </informalexample>
+ **/
+
+/**
+ * g_static_private_init:
+ * @private_key: a #GStaticPrivate to be initialized.
+ *
+ * Initializes @private_key. Alternatively you can initialize it with
+ * #G_STATIC_PRIVATE_INIT.
+ **/
+void
g_static_private_init (GStaticPrivate *private_key)
{
private_key->index = 0;
}
+/**
+ * g_static_private_get:
+ * @private_key: a #GStaticPrivate.
+ * @Returns: the corresponding pointer.
+ *
+ * Works like g_private_get() only for a #GStaticPrivate.
+ *
+ * This function works even if g_thread_init() has not yet been called.
+ **/
gpointer
g_static_private_get (GStaticPrivate *private_key)
{
GRealThread *self = (GRealThread*) g_thread_self ();
GArray *array;
+ gpointer ret = NULL;
+
+ LOCK_PRIVATE_DATA (self);
array = self->private_data;
- if (!array)
- return NULL;
- if (!private_key->index)
- return NULL;
- else if (private_key->index <= array->len)
- return g_array_index (array, GStaticPrivateNode,
- private_key->index - 1).data;
- else
- return NULL;
+ if (array && private_key->index != 0 && private_key->index <= array->len)
+ ret = g_array_index (array, GStaticPrivateNode,
+ private_key->index - 1).data;
+
+ UNLOCK_PRIVATE_DATA (self);
+ return ret;
}
+/**
+ * g_static_private_set:
+ * @private_key: a #GStaticPrivate.
+ * @data: the new pointer.
+ * @notify: a function to be called with the pointer whenever the
+ * current thread ends or sets this pointer again.
+ *
+ * Sets the pointer keyed to @private_key for the current thread and
+ * the function @notify to be called with that pointer (%NULL or
+ * non-%NULL), whenever the pointer is set again or whenever the
+ * current thread ends.
+ *
+ * This function works even if g_thread_init() has not yet been called.
+ * If g_thread_init() is called later, the @data keyed to @private_key
+ * will be inherited only by the main thread, i.e. the one that called
+ * g_thread_init().
+ *
+ * <note><para>@notify is used quite differently from @destructor in
+ * g_private_new().</para></note>
+ **/
void
-g_static_private_set (GStaticPrivate *private_key,
+g_static_private_set (GStaticPrivate *private_key,
gpointer data,
GDestroyNotify notify)
{
GArray *array;
static guint next_index = 0;
GStaticPrivateNode *node;
-
- array = self->private_data;
- if (!array)
- {
- array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
- self->private_data = array;
- }
+ gpointer ddata = NULL;
+ GDestroyNotify ddestroy = NULL;
if (!private_key->index)
{
if (!private_key->index)
{
- if (g_thread_free_indeces)
+ if (g_thread_free_indices)
{
- private_key->index =
- GPOINTER_TO_UINT (g_thread_free_indeces->data);
- g_thread_free_indeces =
- g_slist_delete_link (g_thread_free_indeces,
- g_thread_free_indeces);
+ private_key->index =
+ GPOINTER_TO_UINT (g_thread_free_indices->data);
+ g_thread_free_indices =
+ g_slist_delete_link (g_thread_free_indices,
+ g_thread_free_indices);
}
else
private_key->index = ++next_index;
G_UNLOCK (g_thread);
}
+ LOCK_PRIVATE_DATA (self);
+
+ array = self->private_data;
+ if (!array)
+ {
+ array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
+ self->private_data = array;
+ }
+
if (private_key->index > array->len)
g_array_set_size (array, private_key->index);
node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
- if (node->destroy)
- {
- gpointer ddata = node->data;
- GDestroyNotify ddestroy = node->destroy;
- node->data = data;
- node->destroy = notify;
+ ddata = node->data;
+ ddestroy = node->destroy;
- ddestroy (ddata);
- }
- else
- {
- node->data = data;
- node->destroy = notify;
- }
+ node->data = data;
+ node->destroy = notify;
+
+ UNLOCK_PRIVATE_DATA (self);
+
+ if (ddestroy)
+ ddestroy (ddata);
}
-void
+/**
+ * g_static_private_free:
+ * @private_key: a #GStaticPrivate to be freed.
+ *
+ * Releases all resources allocated to @private_key.
+ *
+ * You don't have to call this functions for a #GStaticPrivate with an
+ * unbounded lifetime, i.e. objects declared 'static', but if you have
+ * a #GStaticPrivate as a member of a structure and the structure is
+ * freed, you should also free the #GStaticPrivate.
+ **/
+void
g_static_private_free (GStaticPrivate *private_key)
{
- guint index = private_key->index;
- GSList *list;
+ guint idx = private_key->index;
+ GRealThread *thread, *next;
+ GArray *garbage = NULL;
- if (!index)
+ if (!idx)
return;
-
+
private_key->index = 0;
G_LOCK (g_thread);
- list = g_thread_all_threads;
- while (list)
+
+ thread = g_thread_all_threads;
+
+ for (thread = g_thread_all_threads; thread; thread = next)
{
- GRealThread *thread = list->data;
- GArray *array = thread->private_data;
- list = list->next;
+ GArray *array;
+
+ next = thread->next;
+
+ LOCK_PRIVATE_DATA (thread);
+
+ array = thread->private_data;
- if (array && index <= array->len)
+ if (array && idx <= array->len)
{
- GStaticPrivateNode *node = &g_array_index (array,
- GStaticPrivateNode,
- index - 1);
+ GStaticPrivateNode *node = &g_array_index (array,
+ GStaticPrivateNode,
+ idx - 1);
gpointer ddata = node->data;
GDestroyNotify ddestroy = node->destroy;
node->data = NULL;
node->destroy = NULL;
- if (ddestroy)
- {
- G_UNLOCK (g_thread);
- ddestroy (ddata);
- G_LOCK (g_thread);
- }
+ if (ddestroy)
+ {
+ /* defer non-trivial destruction til after we've finished
+ * iterating, since we must continue to hold the lock */
+ if (garbage == NULL)
+ garbage = g_array_new (FALSE, TRUE,
+ sizeof (GStaticPrivateNode));
+
+ g_array_set_size (garbage, garbage->len + 1);
+
+ node = &g_array_index (garbage, GStaticPrivateNode,
+ garbage->len - 1);
+ node->data = ddata;
+ node->destroy = ddestroy;
+ }
}
+
+ UNLOCK_PRIVATE_DATA (thread);
}
- g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
- GUINT_TO_POINTER (index));
+ g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
+ GUINT_TO_POINTER (idx));
G_UNLOCK (g_thread);
+
+ if (garbage)
+ {
+ guint i;
+
+ for (i = 0; i < garbage->len; i++)
+ {
+ GStaticPrivateNode *node;
+
+ node = &g_array_index (garbage, GStaticPrivateNode, i);
+ node->destroy (node->data);
+ }
+
+ g_array_free (garbage, TRUE);
+ }
}
+/* GThread Extra Functions {{{1 ------------------------------------------- */
static void
g_thread_cleanup (gpointer data)
{
if (data)
{
GRealThread* thread = data;
- if (thread->private_data)
+ GArray *array;
+
+ LOCK_PRIVATE_DATA (thread);
+ array = thread->private_data;
+ thread->private_data = NULL;
+ UNLOCK_PRIVATE_DATA (thread);
+
+ if (array)
{
- GArray* array = thread->private_data;
guint i;
-
+
for (i = 0; i < array->len; i++ )
{
- GStaticPrivateNode *node =
+ GStaticPrivateNode *node =
&g_array_index (array, GStaticPrivateNode, i);
if (node->destroy)
node->destroy (node->data);
it is, the structure is freed in g_thread_join */
if (!thread->thread.joinable)
{
+ GRealThread *t, *p;
+
G_LOCK (g_thread);
- g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
+ for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
+ {
+ if (t == thread)
+ {
+ if (p)
+ p->next = t->next;
+ else
+ g_thread_all_threads = t->next;
+ break;
+ }
+ }
G_UNLOCK (g_thread);
-
+
/* Just to make sure, this isn't used any more */
g_system_thread_assign (thread->system_thread, zero_thread);
- g_free (thread);
+ g_free (thread);
}
}
}
g_error ("The thread system is not yet initialized.");
}
+#define G_NSEC_PER_SEC 1000000000
+
+static guint64
+gettime (void)
+{
+#ifdef G_OS_WIN32
+ guint64 v;
+
+ /* Returns 100s of nanoseconds since start of 1601 */
+ GetSystemTimeAsFileTime ((FILETIME *)&v);
+
+ /* Offset to Unix epoch */
+ v -= G_GINT64_CONSTANT (116444736000000000);
+ /* Convert to nanoseconds */
+ v *= 100;
+
+ return v;
+#else
+ struct timeval tv;
+
+ gettimeofday (&tv, NULL);
+
+ return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
+#endif
+}
+
static gpointer
g_thread_create_proxy (gpointer data)
{
before thread->thread.func is called. See g_thread_create. */
G_LOCK (g_thread);
G_UNLOCK (g_thread);
-
+
thread->retval = thread->thread.func (thread->thread.data);
return NULL;
}
-GThread*
-g_thread_create_full (GThreadFunc func,
- gpointer data,
- gulong stack_size,
- gboolean joinable,
- gboolean bound,
- GThreadPriority priority,
- GError **error)
+/**
+ * g_thread_create_full:
+ * @func: a function to execute in the new thread.
+ * @data: an argument to supply to the new thread.
+ * @stack_size: a stack size for the new thread.
+ * @joinable: should this thread be joinable?
+ * @bound: should this thread be bound to a system thread?
+ * @priority: a priority for the thread.
+ * @error: return location for error.
+ * @Returns: the new #GThread on success.
+ *
+ * This function creates a new thread with the priority @priority. If
+ * the underlying thread implementation supports it, the thread gets a
+ * stack size of @stack_size or the default value for the current
+ * platform, if @stack_size is 0.
+ *
+ * If @joinable is %TRUE, you can wait for this threads termination
+ * calling g_thread_join(). Otherwise the thread will just disappear
+ * when it terminates. If @bound is %TRUE, this thread will be
+ * scheduled in the system scope, otherwise the implementation is free
+ * to do scheduling in the process scope. The first variant is more
+ * expensive resource-wise, but generally faster. On some systems (e.g.
+ * Linux) all threads are bound.
+ *
+ * The new thread executes the function @func with the argument @data.
+ * If the thread was created successfully, it is returned.
+ *
+ * @error can be %NULL to ignore errors, or non-%NULL to report errors.
+ * The error is set, if and only if the function returns %NULL.
+ *
+ * <note><para>It is not guaranteed that threads with different priorities
+ * really behave accordingly. On some systems (e.g. Linux) there are no
+ * thread priorities. On other systems (e.g. Solaris) there doesn't
+ * seem to be different scheduling for different priorities. All in all
+ * try to avoid being dependent on priorities. Use
+ * %G_THREAD_PRIORITY_NORMAL here as a default.</para></note>
+ *
+ * <note><para>Only use g_thread_create_full() if you really can't use
+ * g_thread_create() instead. g_thread_create() does not take
+ * @stack_size, @bound, and @priority as arguments, as they should only
+ * be used in cases in which it is unavoidable.</para></note>
+ **/
+GThread*
+g_thread_create_full (GThreadFunc func,
+ gpointer data,
+ gulong stack_size,
+ gboolean joinable,
+ gboolean bound,
+ GThreadPriority priority,
+ GError **error)
{
GRealThread* result;
GError *local_error = NULL;
g_return_val_if_fail (func, NULL);
g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
-
- result = g_new (GRealThread, 1);
+
+ result = g_new0 (GRealThread, 1);
result->thread.joinable = joinable;
result->thread.priority = priority;
result->thread.func = func;
result->thread.data = data;
- result->private_data = NULL;
+ result->private_data = NULL;
G_LOCK (g_thread);
- G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
+ G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
stack_size, joinable, bound, priority,
&result->system_thread, &local_error));
- g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
+ if (!local_error)
+ {
+ result->next = g_thread_all_threads;
+ g_thread_all_threads = result;
+ }
G_UNLOCK (g_thread);
if (local_error)
return (GThread*) result;
}
+/**
+ * g_thread_exit:
+ * @retval: the return value of this thread.
+ *
+ * Exits the current thread. If another thread is waiting for that
+ * thread using g_thread_join() and the current thread is joinable, the
+ * waiting thread will be woken up and get @retval as the return value
+ * of g_thread_join(). If the current thread is not joinable, @retval
+ * is ignored. Calling
+ *
+ * <informalexample>
+ * <programlisting>
+ * g_thread_exit (retval);
+ * </programlisting>
+ * </informalexample>
+ *
+ * is equivalent to returning @retval from the function @func, as given
+ * to g_thread_create().
+ *
+ * <note><para>Never call g_thread_exit() from within a thread of a
+ * #GThreadPool, as that will mess up the bookkeeping and lead to funny
+ * and unwanted results.</para></note>
+ **/
void
g_thread_exit (gpointer retval)
{
G_THREAD_CF (thread_exit, (void)0, ());
}
+/**
+ * g_thread_join:
+ * @thread: a #GThread to be waited for.
+ * @Returns: the return value of the thread.
+ *
+ * Waits until @thread finishes, i.e. the function @func, as given to
+ * g_thread_create(), returns or g_thread_exit() is called by @thread.
+ * All resources of @thread including the #GThread struct are released.
+ * @thread must have been created with @joinable=%TRUE in
+ * g_thread_create(). The value returned by @func or given to
+ * g_thread_exit() by @thread is returned by this function.
+ **/
gpointer
g_thread_join (GThread* thread)
{
GRealThread* real = (GRealThread*) thread;
+ GRealThread *p, *t;
gpointer retval;
g_return_val_if_fail (thread, NULL);
g_return_val_if_fail (thread->joinable, NULL);
- g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
+ g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
zero_thread), NULL);
G_THREAD_UF (thread_join, (&real->system_thread));
retval = real->retval;
G_LOCK (g_thread);
- g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
+ for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
+ {
+ if (t == (GRealThread*) thread)
+ {
+ if (p)
+ p->next = t->next;
+ else
+ g_thread_all_threads = t->next;
+ break;
+ }
+ }
G_UNLOCK (g_thread);
/* Just to make sure, this isn't used any more */
return retval;
}
+/**
+ * g_thread_set_priority:
+ * @thread: a #GThread.
+ * @priority: a new priority for @thread.
+ *
+ * Changes the priority of @thread to @priority.
+ *
+ * <note><para>It is not guaranteed that threads with different
+ * priorities really behave accordingly. On some systems (e.g. Linux)
+ * there are no thread priorities. On other systems (e.g. Solaris) there
+ * doesn't seem to be different scheduling for different priorities. All
+ * in all try to avoid being dependent on priorities.</para></note>
+ **/
void
-g_thread_set_priority (GThread* thread,
+g_thread_set_priority (GThread* thread,
GThreadPriority priority)
{
GRealThread* real = (GRealThread*) thread;
thread->priority = priority;
- G_THREAD_CF (thread_set_priority, (void)0,
+ G_THREAD_CF (thread_set_priority, (void)0,
(&real->system_thread, priority));
}
+/**
+ * g_thread_self:
+ * @Returns: the current thread.
+ *
+ * This functions returns the #GThread corresponding to the calling
+ * thread.
+ **/
GThread*
g_thread_self (void)
{
GRealThread* thread = g_private_get (g_thread_specific_private);
if (!thread)
- {
+ {
/* If no thread data is available, provide and set one. This
can happen for the main thread and for threads, that are not
created by GLib. */
- thread = g_new (GRealThread, 1);
+ thread = g_new0 (GRealThread, 1);
thread->thread.joinable = FALSE; /* This is a save guess */
thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
just a guess */
if (g_thread_supported ())
G_THREAD_UF (thread_self, (&thread->system_thread));
- g_private_set (g_thread_specific_private, thread);
-
+ g_private_set (g_thread_specific_private, thread);
+
G_LOCK (g_thread);
- g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
+ thread->next = g_thread_all_threads;
+ g_thread_all_threads = thread;
G_UNLOCK (g_thread);
}
-
+
return (GThread*)thread;
}
+/* GStaticRWLock {{{1 ----------------------------------------------------- */
+
+/**
+ * GStaticRWLock:
+ *
+ * The #GStaticRWLock struct represents a read-write lock. A read-write
+ * lock can be used for protecting data that some portions of code only
+ * read from, while others also write. In such situations it is
+ * desirable that several readers can read at once, whereas of course
+ * only one writer may write at a time. Take a look at the following
+ * example:
+ *
+ * <example>
+ * <title>An array with access functions</title>
+ * <programlisting>
+ * GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
+ * GPtrArray *array;
+ *
+ * gpointer
+ * my_array_get (guint index)
+ * {
+ * gpointer retval = NULL;
+ *
+ * if (!array)
+ * return NULL;
+ *
+ * g_static_rw_lock_reader_lock (&rwlock);
+ * if (index < array->len)
+ * retval = g_ptr_array_index (array, index);
+ * g_static_rw_lock_reader_unlock (&rwlock);
+ *
+ * return retval;
+ * }
+ *
+ * void
+ * my_array_set (guint index, gpointer data)
+ * {
+ * g_static_rw_lock_writer_lock (&rwlock);
+ *
+ * if (!array)
+ * array = g_ptr_array_new (<!-- -->);
+ *
+ * if (index >= array->len)
+ * g_ptr_array_set_size (array, index+1);
+ * g_ptr_array_index (array, index) = data;
+ *
+ * g_static_rw_lock_writer_unlock (&rwlock);
+ * }
+ * </programlisting>
+ * </example>
+ *
+ * This example shows an array which can be accessed by many readers
+ * (the <function>my_array_get()</function> function) simultaneously,
+ * whereas the writers (the <function>my_array_set()</function>
+ * function) will only be allowed once at a time and only if no readers
+ * currently access the array. This is because of the potentially
+ * dangerous resizing of the array. Using these functions is fully
+ * multi-thread safe now.
+ *
+ * Most of the time, writers should have precedence over readers. That
+ * means, for this implementation, that as soon as a writer wants to
+ * lock the data, no other reader is allowed to lock the data, whereas,
+ * of course, the readers that already have locked the data are allowed
+ * to finish their operation. As soon as the last reader unlocks the
+ * data, the writer will lock it.
+ *
+ * Even though #GStaticRWLock is not opaque, it should only be used
+ * with the following functions.
+ *
+ * All of the <function>g_static_rw_lock_*</function> functions can be
+ * used even if g_thread_init() has not been called. Then they do
+ * nothing, apart from <function>g_static_rw_lock_*_trylock</function>,
+ * which does nothing but returning %TRUE.
+ *
+ * <note><para>A read-write lock has a higher overhead than a mutex. For
+ * example, both g_static_rw_lock_reader_lock() and
+ * g_static_rw_lock_reader_unlock() have to lock and unlock a
+ * #GStaticMutex, so it takes at least twice the time to lock and unlock
+ * a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
+ * only data structures that are accessed by multiple readers, and which
+ * keep the lock for a considerable time justify a #GStaticRWLock. The
+ * above example most probably would fare better with a
+ * #GStaticMutex.</para></note>
+ **/
+
+/**
+ * G_STATIC_RW_LOCK_INIT:
+ *
+ * A #GStaticRWLock must be initialized with this macro before it can
+ * be used. This macro can used be to initialize a variable, but it
+ * cannot be assigned to a variable. In that case you have to use
+ * g_static_rw_lock_init().
+ *
+ * <informalexample>
+ * <programlisting>
+ * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
+ * </programlisting>
+ * </informalexample>
+ **/
+
+/**
+ * g_static_rw_lock_init:
+ * @lock: a #GStaticRWLock to be initialized.
+ *
+ * A #GStaticRWLock must be initialized with this function before it
+ * can be used. Alternatively you can initialize it with
+ * #G_STATIC_RW_LOCK_INIT.
+ **/
void
g_static_rw_lock_init (GStaticRWLock* lock)
{
- static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
+ static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
g_return_if_fail (lock);
*lock = init_lock;
}
-static void inline
+inline static void
g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
{
if (!*cond)
g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
}
-static void inline
+inline static void
g_static_rw_lock_signal (GStaticRWLock* lock)
{
if (lock->want_to_write && lock->write_cond)
g_cond_broadcast (lock->read_cond);
}
-void
+/**
+ * g_static_rw_lock_reader_lock:
+ * @lock: a #GStaticRWLock to lock for reading.
+ *
+ * Locks @lock for reading. There may be unlimited concurrent locks for
+ * reading of a #GStaticRWLock at the same time. If @lock is already
+ * locked for writing by another thread or if another thread is already
+ * waiting to lock @lock for writing, this function will block until
+ * @lock is unlocked by the other writing thread and no other writing
+ * threads want to lock @lock. This lock has to be unlocked by
+ * g_static_rw_lock_reader_unlock().
+ *
+ * #GStaticRWLock is not recursive. It might seem to be possible to
+ * recursively lock for reading, but that can result in a deadlock, due
+ * to writer preference.
+ **/
+void
g_static_rw_lock_reader_lock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
g_static_mutex_lock (&lock->mutex);
lock->want_to_read++;
- while (lock->have_writer || lock->want_to_write)
+ while (lock->have_writer || lock->want_to_write)
g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
lock->want_to_read--;
lock->read_counter++;
g_static_mutex_unlock (&lock->mutex);
}
-gboolean
+/**
+ * g_static_rw_lock_reader_trylock:
+ * @lock: a #GStaticRWLock to lock for reading.
+ * @Returns: %TRUE, if @lock could be locked for reading.
+ *
+ * Tries to lock @lock for reading. If @lock is already locked for
+ * writing by another thread or if another thread is already waiting to
+ * lock @lock for writing, immediately returns %FALSE. Otherwise locks
+ * @lock for reading and returns %TRUE. This lock has to be unlocked by
+ * g_static_rw_lock_reader_unlock().
+ **/
+gboolean
g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
{
gboolean ret_val = FALSE;
return ret_val;
}
-void
+/**
+ * g_static_rw_lock_reader_unlock:
+ * @lock: a #GStaticRWLock to unlock after reading.
+ *
+ * Unlocks @lock. If a thread waits to lock @lock for writing and all
+ * locks for reading have been unlocked, the waiting thread is woken up
+ * and can lock @lock for writing.
+ **/
+void
g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
g_static_mutex_unlock (&lock->mutex);
}
-void
+/**
+ * g_static_rw_lock_writer_lock:
+ * @lock: a #GStaticRWLock to lock for writing.
+ *
+ * Locks @lock for writing. If @lock is already locked for writing or
+ * reading by other threads, this function will block until @lock is
+ * completely unlocked and then lock @lock for writing. While this
+ * functions waits to lock @lock, no other thread can lock @lock for
+ * reading. When @lock is locked for writing, no other thread can lock
+ * @lock (neither for reading nor writing). This lock has to be
+ * unlocked by g_static_rw_lock_writer_unlock().
+ **/
+void
g_static_rw_lock_writer_lock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
g_static_mutex_unlock (&lock->mutex);
}
-gboolean
+/**
+ * g_static_rw_lock_writer_trylock:
+ * @lock: a #GStaticRWLock to lock for writing.
+ * @Returns: %TRUE, if @lock could be locked for writing.
+ *
+ * Tries to lock @lock for writing. If @lock is already locked (for
+ * either reading or writing) by another thread, it immediately returns
+ * %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
+ * lock has to be unlocked by g_static_rw_lock_writer_unlock().
+ **/
+gboolean
g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
{
gboolean ret_val = FALSE;
g_return_val_if_fail (lock, FALSE);
-
+
if (!g_threads_got_initialized)
return TRUE;
return ret_val;
}
-void
+/**
+ * g_static_rw_lock_writer_unlock:
+ * @lock: a #GStaticRWLock to unlock after writing.
+ *
+ * Unlocks @lock. If a thread is waiting to lock @lock for writing and
+ * all locks for reading have been unlocked, the waiting thread is
+ * woken up and can lock @lock for writing. If no thread is waiting to
+ * lock @lock for writing, and some thread or threads are waiting to
+ * lock @lock for reading, the waiting threads are woken up and can
+ * lock @lock for reading.
+ **/
+void
g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
-
+
if (!g_threads_got_initialized)
return;
g_static_mutex_lock (&lock->mutex);
- lock->have_writer = FALSE;
+ lock->have_writer = FALSE;
g_static_rw_lock_signal (lock);
g_static_mutex_unlock (&lock->mutex);
}
-void
+/**
+ * g_static_rw_lock_free:
+ * @lock: a #GStaticRWLock to be freed.
+ *
+ * Releases all resources allocated to @lock.
+ *
+ * You don't have to call this functions for a #GStaticRWLock with an
+ * unbounded lifetime, i.e. objects declared 'static', but if you have
+ * a #GStaticRWLock as a member of a structure, and the structure is
+ * freed, you should also free the #GStaticRWLock.
+ **/
+void
g_static_rw_lock_free (GStaticRWLock* lock)
{
g_return_if_fail (lock);
-
+
if (lock->read_cond)
{
g_cond_free (lock->read_cond);
}
g_static_mutex_free (&lock->mutex);
}
+
+/* Unsorted {{{1 ---------------------------------------------------------- */
+
+/**
+ * g_thread_foreach
+ * @thread_func: function to call for all GThread structures
+ * @user_data: second argument to @thread_func
+ *
+ * Call @thread_func on all existing #GThread structures. Note that
+ * threads may decide to exit while @thread_func is running, so
+ * without intimate knowledge about the lifetime of foreign threads,
+ * @thread_func shouldn't access the GThread* pointer passed in as
+ * first argument. However, @thread_func will not be called for threads
+ * which are known to have exited already.
+ *
+ * Due to thread lifetime checks, this function has an execution complexity
+ * which is quadratic in the number of existing threads.
+ *
+ * Since: 2.10
+ */
+void
+g_thread_foreach (GFunc thread_func,
+ gpointer user_data)
+{
+ GSList *slist = NULL;
+ GRealThread *thread;
+ g_return_if_fail (thread_func != NULL);
+ /* snapshot the list of threads for iteration */
+ G_LOCK (g_thread);
+ for (thread = g_thread_all_threads; thread; thread = thread->next)
+ slist = g_slist_prepend (slist, thread);
+ G_UNLOCK (g_thread);
+ /* walk the list, skipping non-existant threads */
+ while (slist)
+ {
+ GSList *node = slist;
+ slist = node->next;
+ /* check whether the current thread still exists */
+ G_LOCK (g_thread);
+ for (thread = g_thread_all_threads; thread; thread = thread->next)
+ if (thread == node->data)
+ break;
+ G_UNLOCK (g_thread);
+ if (thread)
+ thread_func (thread, user_data);
+ g_slist_free_1 (node);
+ }
+}
+
+/**
+ * g_thread_get_initialized
+ *
+ * Indicates if g_thread_init() has been called.
+ *
+ * Returns: %TRUE if threads have been initialized.
+ *
+ * Since: 2.20
+ */
+gboolean
+g_thread_get_initialized ()
+{
+ return g_thread_supported ();
+}
projects / platform / upstream / glib.git / blobdiff