* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
+/* 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"
-#ifdef HAVE_UNISTD_H
+#include "gthread.h"
+#include "gthreadprivate.h"
+
+#include <string.h>
+
+#ifdef G_OS_UNIX
#include <unistd.h>
#endif
-#include <string.h>
+#ifndef G_OS_WIN32
+#include <sys/time.h>
+#include <time.h>
+#else
+#include <windows.h>
+#endif /* G_OS_WIN32 */
+
+#include "gslice.h"
+#include "gstrfuncs.h"
+#include "gtestutils.h"
+
+/**
+ * SECTION:threads
+ * @title: Threads
+ * @short_description: portable support for threads, mutexes, locks,
+ * 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, #GRecMutex and #GRWLock). 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). There are facilities
+ * for one-time initialization (#GOnce, g_once_init_enter()). Finally,
+ * there are primitives to create and manage threads (#GThread).
+ *
+ * The GLib threading system used to be initialized with g_thread_init().
+ * This is no longer necessary. Since version 2.32, the GLib threading
+ * system is automatically initialized at the start of your program,
+ * and all thread-creation functions and synchronization primitives
+ * are available right away.
+ *
+ * Note that it is not safe to assume that your program has no threads
+ * even if you don't call g_thread_new() yourself. GLib and GIO can
+ * and will create threads for their own purposes in some cases, such
+ * as when using g_unix_signal_source_new() or when using GDBus.
+ *
+ * Originally, UNIX did not have threads, and therefore some traditional
+ * UNIX APIs are problematic in threaded programs. Some notable examples
+ * are
+ *
+ * - C library functions that return data in statically allocated
+ * buffers, such as strtok() or strerror(). For many of these,
+ * there are thread-safe variants with a _r suffix, or you can
+ * look at corresponding GLib APIs (like g_strsplit() or g_strerror()).
+ *
+ * - The functions setenv() and unsetenv() manipulate the process
+ * environment in a not thread-safe way, and may interfere with getenv()
+ * calls in other threads. Note that getenv() calls may be hidden behind
+ * other APIs. For example, GNU gettext() calls getenv() under the
+ * covers. In general, it is best to treat the environment as readonly.
+ * If you absolutely have to modify the environment, do it early in
+ * main(), when no other threads are around yet.
+ *
+ * - The setlocale() function changes the locale for the entire process,
+ * affecting all threads. Temporary changes to the locale are often made
+ * to change the behavior of string scanning or formatting functions
+ * like scanf() or printf(). GLib offers a number of string APIs
+ * (like g_ascii_formatd() or g_ascii_strtod()) that can often be
+ * used as an alternative. Or you can use the uselocale() function
+ * to change the locale only for the current thread.
+ *
+ * - The fork() function only takes the calling thread into the child's
+ * copy of the process image. If other threads were executing in critical
+ * sections they could have left mutexes locked which could easily
+ * cause deadlocks in the new child. For this reason, you should
+ * call exit() or exec() as soon as possible in the child and only
+ * make signal-safe library calls before that.
+ *
+ * - The daemon() function uses fork() in a way contrary to what is
+ * described above. It should not be used with GLib programs.
+ *
+ * GLib itself is internally completely thread-safe (all global data is
+ * automatically locked), but individual data structure instances are
+ * not automatically locked for performance reasons. 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 are thread-safe and need no further
+ * application-level locking to be accessed from multiple threads.
+ * Most refcounting functions such as g_object_ref() are also thread-safe.
+ */
-#include "glib.h"
-#include "gthreadinit.h"
-#include "galias.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
-g_thread_error_quark (void)
-{
- static GQuark quark;
- if (!quark)
- quark = g_quark_from_static_string ("g_thread_error");
- return quark;
-}
+/* G_LOCK Documentation {{{1 ---------------------------------------------- */
-/* Keep this in sync with GRealThread in gmain.c! */
-typedef struct _GRealThread GRealThread;
-struct _GRealThread
-{
- GThread thread;
- gpointer private_data;
- gpointer retval;
- GSystemThread system_thread;
-};
+/**
+ * G_LOCK_DEFINE:
+ * @name: the name of the lock
+ *
+ * The #G_LOCK_ macros provide a convenient interface to #GMutex.
+ * #G_LOCK_DEFINE defines a lock. It can appear in any place where
+ * 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 #GMutex. This means that you
+ * can use names of existing variables as the parameter - e.g. the name
+ * of the variable you intend to protect with the lock. Look at our
+ * give_me_next_number() example using the #G_LOCK macros:
+ *
+ * Here is an example for using the #G_LOCK convenience macros:
+ * |[<!-- language="C" -->
+ * 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;
+ * }
+ * ]|
+ */
-typedef struct _GStaticPrivateNode GStaticPrivateNode;
-struct _GStaticPrivateNode
-{
- gpointer data;
- GDestroyNotify destroy;
-};
+/**
+ * G_LOCK_DEFINE_STATIC:
+ * @name: the name of the lock
+ *
+ * This works like #G_LOCK_DEFINE, but it creates a static object.
+ */
-static void g_thread_cleanup (gpointer data);
-static void g_thread_fail (void);
-
-/* Global variables */
-
-static GSystemThread zero_thread; /* This is initialized to all zero */
-gboolean g_thread_use_default_impl = TRUE;
-gboolean g_threads_got_initialized = FALSE;
-
-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 */
- NULL, /* thread_join */
- NULL, /* thread_exit */
- NULL, /* thread_set_priority */
- NULL /* thread_self */
-};
-
-/* Local data */
-
-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;
-
-G_LOCK_DEFINE_STATIC (g_thread);
-
-#ifdef G_THREADS_ENABLED
-/* This must be called only once, before any threads are created.
- * It will only be called from g_thread_init() in -lgthread.
+/**
+ * G_LOCK_EXTERN:
+ * @name: the name of the lock
+ *
+ * This declares a lock, that is defined with #G_LOCK_DEFINE in another
+ * module.
*/
-void
-g_thread_init_glib (void)
-{
- /* We let the main thread (the one that calls g_thread_init) inherit
- * the static_private data set before calling g_thread_init
- */
- GRealThread* main_thread = (GRealThread*) g_thread_self ();
-
- 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 ();
- _g_utils_thread_init ();
-#ifdef G_OS_WIN32
- _g_win32_thread_init ();
-#endif
- g_threads_got_initialized = TRUE;
+/**
+ * G_LOCK:
+ * @name: the name of the lock
+ *
+ * Works like g_mutex_lock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ */
- 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_TRYLOCK:
+ * @name: the name of the lock
+ *
+ * Works like g_mutex_trylock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ *
+ * Returns: %TRUE, if the lock could be locked.
+ */
- _g_mem_thread_private_init ();
- _g_messages_thread_private_init ();
+/**
+ * G_UNLOCK:
+ * @name: the name of the lock
+ *
+ * Works like g_mutex_unlock(), but for a lock defined with
+ * #G_LOCK_DEFINE.
+ */
-}
-#endif /* G_THREADS_ENABLED */
+/* GMutex Documentation {{{1 ------------------------------------------ */
-gpointer
-g_once_impl (GOnce *once,
- GThreadFunc func,
- gpointer arg)
-{
- g_mutex_lock (g_once_mutex);
+/**
+ * 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:
+ * |[<!-- language="C" -->
+ * 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;
+ * }
+ * ]|
+ * 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 #GMutex can be used as a solution to this problem:
+ * |[<!-- language="C" -->
+ * int
+ * give_me_next_number (void)
+ * {
+ * static GMutex mutex;
+ * static int current_number = 0;
+ * int ret_val;
+ *
+ * g_mutex_lock (&mutex);
+ * ret_val = current_number = calc_next_number (current_number);
+ * g_mutex_unlock (&mutex);
+ *
+ * return ret_val;
+ * }
+ * ]|
+ * Notice that the #GMutex is not initialised to any particular value.
+ * Its placement in static storage ensures that it will be initialised
+ * to all-zeros, which is appropriate.
+ *
+ * If a #GMutex is placed in other contexts (eg: embedded in a struct)
+ * then it must be explicitly initialised using g_mutex_init().
+ *
+ * A #GMutex should only be accessed via g_mutex_ functions.
+ */
- 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);
+/* GRecMutex Documentation {{{1 -------------------------------------- */
- 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;
-}
+/**
+ * GRecMutex:
+ *
+ * The GRecMutex struct is an opaque data structure to represent a
+ * recursive mutex. It is similar to a #GMutex with the difference
+ * that it is possible to lock a GRecMutex multiple times in the same
+ * thread without deadlock. When doing so, care has to be taken to
+ * unlock the recursive mutex as often as it has been locked.
+ *
+ * If a #GRecMutex is allocated in static storage then it can be used
+ * without initialisation. Otherwise, you should call
+ * g_rec_mutex_init() on it and g_rec_mutex_clear() when done.
+ *
+ * A GRecMutex should only be accessed with the
+ * g_rec_mutex_ functions.
+ *
+ * Since: 2.32
+ */
-void
-g_static_mutex_init (GStaticMutex *mutex)
-{
- static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
+/* GRWLock Documentation {{{1 ---------------------------------------- */
+
+/**
+ * GRWLock:
+ *
+ * The GRWLock struct is an opaque data structure to represent a
+ * reader-writer lock. It is similar to a #GMutex in that it allows
+ * multiple threads to coordinate access to a shared resource.
+ *
+ * The difference to a mutex is that a reader-writer lock discriminates
+ * between read-only ('reader') and full ('writer') access. While only
+ * one thread at a time is allowed write access (by holding the 'writer'
+ * lock via g_rw_lock_writer_lock()), multiple threads can gain
+ * simultaneous read-only access (by holding the 'reader' lock via
+ * g_rw_lock_reader_lock()).
+ *
+ * Here is an example for an array with access functions:
+ * |[<!-- language="C" -->
+ * GRWLock lock;
+ * GPtrArray *array;
+ *
+ * gpointer
+ * my_array_get (guint index)
+ * {
+ * gpointer retval = NULL;
+ *
+ * if (!array)
+ * return NULL;
+ *
+ * g_rw_lock_reader_lock (&lock);
+ * if (index < array->len)
+ * retval = g_ptr_array_index (array, index);
+ * g_rw_lock_reader_unlock (&lock);
+ *
+ * return retval;
+ * }
+ *
+ * void
+ * my_array_set (guint index, gpointer data)
+ * {
+ * g_rw_lock_writer_lock (&lock);
+ *
+ * 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_rw_lock_writer_unlock (&lock);
+ * }
+ * ]|
+ * This example shows an array which can be accessed by many readers
+ * (the my_array_get() function) simultaneously, whereas the writers
+ * (the my_array_set() function) will only be allowed one 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.
+ *
+ * If a #GRWLock is allocated in static storage then it can be used
+ * without initialisation. Otherwise, you should call
+ * g_rw_lock_init() on it and g_rw_lock_clear() when done.
+ *
+ * A GRWLock should only be accessed with the g_rw_lock_ functions.
+ *
+ * Since: 2.32
+ */
- g_return_if_fail (mutex);
+/* GCond Documentation {{{1 ------------------------------------------ */
- *mutex = init_mutex;
-}
+/**
+ * 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.
+ *
+ * Consider the following example of a shared variable. One or more
+ * threads can wait for data to be published to the variable and when
+ * another thread publishes the data, it can signal one of the waiting
+ * threads to wake up to collect the data.
+ *
+ * Here is an example for using GCond to block a thread until a condition
+ * is satisfied:
+ * |[<!-- language="C" -->
+ * gpointer current_data = NULL;
+ * GMutex data_mutex;
+ * GCond data_cond;
+ *
+ * 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;
+ * }
+ * ]|
+ * Whenever a thread calls pop_data() now, it will wait until
+ * current_data is non-%NULL, i.e. until some other thread
+ * has called push_data().
+ *
+ * The example shows that use of a condition variable must always be
+ * paired with a mutex. Without the use of a mutex, there would be a
+ * race between the check of @current_data by the while loop in
+ * pop_data() and waiting. Specifically, another thread could set
+ * @current_data after the check, and signal the cond (with nobody
+ * waiting on it) before the first thread goes to sleep. #GCond is
+ * specifically useful for its ability to release the mutex and go
+ * to sleep atomically.
+ *
+ * It is also important to use the g_cond_wait() and g_cond_wait_until()
+ * functions only inside a loop which checks for the condition to be
+ * true. See g_cond_wait() for an explanation of why the condition may
+ * not be true even after it returns.
+ *
+ * If a #GCond is allocated in static storage then it can be used
+ * without initialisation. Otherwise, you should call g_cond_init()
+ * on it and g_cond_clear() when done.
+ *
+ * A #GCond should only be accessed via the g_cond_ functions.
+ */
-GMutex *
-g_static_mutex_get_mutex_impl (GMutex** mutex)
-{
- if (!g_thread_supported ())
- return NULL;
+/* GThread Documentation {{{1 ---------------------------------------- */
- g_assert (g_once_mutex);
+/**
+ * GThread:
+ *
+ * The #GThread struct represents a running thread. This struct
+ * is returned by g_thread_new() or g_thread_try_new(). You can
+ * obtain the #GThread struct representing the current thread by
+ * calling g_thread_self().
+ *
+ * GThread is refcounted, see g_thread_ref() and g_thread_unref().
+ * The thread represented by it holds a reference while it is running,
+ * and g_thread_join() consumes the reference that it is given, so
+ * it is normally not necessary to manage GThread references
+ * explicitly.
+ *
+ * The structure is opaque -- none of its fields may be directly
+ * accessed.
+ */
- g_mutex_lock (g_once_mutex);
+/**
+ * GThreadFunc:
+ * @data: data passed to the thread
+ *
+ * Specifies the type of the @func functions passed to g_thread_new()
+ * or g_thread_try_new().
+ *
+ * Returns: the return value of the thread
+ */
- if (!(*mutex))
- {
- 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_thread_supported:
+ *
+ * This macro returns %TRUE if the thread system is initialized,
+ * and %FALSE if it is not.
+ *
+ * For language bindings, g_thread_get_initialized() provides
+ * the same functionality as a function.
+ *
+ * Returns: %TRUE, if the thread system is initialized
+ */
- g_mutex_unlock (g_once_mutex);
-
- return *mutex;
-}
+/* 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.
+ **/
-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 */
- runtime_mutex = ((GMutex**)mutex);
-
- if (*runtime_mutex)
- g_mutex_free (*runtime_mutex);
-
- *runtime_mutex = NULL;
-}
+/**
+ * G_THREAD_ERROR:
+ *
+ * The error domain of the GLib thread subsystem.
+ **/
+G_DEFINE_QUARK (g_thread_error, g_thread_error)
-void
-g_static_rec_mutex_init (GStaticRecMutex *mutex)
-{
- static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
-
- g_return_if_fail (mutex);
+/* Local Data {{{1 -------------------------------------------------------- */
- *mutex = init_mutex;
-}
+static GMutex g_once_mutex;
+static GCond g_once_cond;
+static GSList *g_once_init_list = NULL;
-void
-g_static_rec_mutex_lock (GStaticRecMutex* mutex)
-{
- GSystemThread self;
+static void g_thread_cleanup (gpointer data);
+static GPrivate g_thread_specific_private = G_PRIVATE_INIT (g_thread_cleanup);
- g_return_if_fail (mutex);
+G_LOCK_DEFINE_STATIC (g_thread_new);
- if (!g_thread_supported ())
- return;
+/* GOnce {{{1 ------------------------------------------------------------- */
- G_THREAD_UF (thread_self, (&self));
+/**
+ * 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
+ */
- if (g_system_thread_equal (self, mutex->owner))
- {
- mutex->depth++;
- return;
- }
- g_static_mutex_lock (&mutex->mutex);
- g_system_thread_assign (mutex->owner, self);
- mutex->depth = 1;
-}
+/**
+ * G_ONCE_INIT:
+ *
+ * A #GOnce must be initialized with this macro before it can be used.
+ *
+ * |[<!-- language="C" -->
+ * GOnce my_once = G_ONCE_INIT;
+ * ]|
+ *
+ * Since: 2.4
+ */
-gboolean
-g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
+/**
+ * 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.
+ *
+ * Calling g_once() recursively on the same #GOnce struct in
+ * @func will lead to a deadlock.
+ *
+ * |[<!-- language="C" -->
+ * gpointer
+ * get_debug_flags (void)
+ * {
+ * static GOnce my_once = G_ONCE_INIT;
+ *
+ * g_once (&my_once, parse_debug_flags, NULL);
+ *
+ * return my_once.retval;
+ * }
+ * ]|
+ *
+ * Since: 2.4
+ */
+gpointer
+g_once_impl (GOnce *once,
+ GThreadFunc func,
+ gpointer arg)
{
- GSystemThread self;
+ g_mutex_lock (&g_once_mutex);
- g_return_val_if_fail (mutex, FALSE);
+ while (once->status == G_ONCE_STATUS_PROGRESS)
+ g_cond_wait (&g_once_cond, &g_once_mutex);
- if (!g_thread_supported ())
- return TRUE;
+ if (once->status != G_ONCE_STATUS_READY)
+ {
+ once->status = G_ONCE_STATUS_PROGRESS;
+ g_mutex_unlock (&g_once_mutex);
- G_THREAD_UF (thread_self, (&self));
+ once->retval = func (arg);
- if (g_system_thread_equal (self, mutex->owner))
- {
- mutex->depth++;
- return TRUE;
+ g_mutex_lock (&g_once_mutex);
+ once->status = G_ONCE_STATUS_READY;
+ g_cond_broadcast (&g_once_cond);
}
- if (!g_static_mutex_trylock (&mutex->mutex))
- return FALSE;
+ g_mutex_unlock (&g_once_mutex);
- g_system_thread_assign (mutex->owner, self);
- mutex->depth = 1;
- return TRUE;
+ return once->retval;
}
-void
-g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
+/**
+ * g_once_init_enter:
+ * @location: location of a static initializable variable containing 0
+ *
+ * Function to be called when starting a critical initialization
+ * section. The argument @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:
+ *
+ * |[<!-- language="C" -->
+ * 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
+ * ]|
+ *
+ * Returns: %TRUE if the initialization section should be entered,
+ * %FALSE and blocks otherwise
+ *
+ * Since: 2.14
+ */
+gboolean
+(g_once_init_enter) (volatile void *location)
{
- g_return_if_fail (mutex);
-
- if (!g_thread_supported ())
- return;
-
- if (mutex->depth > 1)
+ volatile gsize *value_location = location;
+ gboolean need_init = FALSE;
+ g_mutex_lock (&g_once_mutex);
+ if (g_atomic_pointer_get (value_location) == NULL)
{
- mutex->depth--;
- return;
+ 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_system_thread_assign (mutex->owner, zero_thread);
- g_static_mutex_unlock (&mutex->mutex);
+ g_mutex_unlock (&g_once_mutex);
+ return need_init;
}
+/**
+ * g_once_init_leave:
+ * @location: location of a static initializable variable containing 0
+ * @result: 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_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
- guint depth)
+(g_once_init_leave) (volatile void *location,
+ gsize result)
{
- GSystemThread self;
- g_return_if_fail (mutex);
-
- if (!g_thread_supported ())
- return;
+ volatile gsize *value_location = location;
- G_THREAD_UF (thread_self, (&self));
+ g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
+ g_return_if_fail (result != 0);
+ g_return_if_fail (g_once_init_list != NULL);
- if (g_system_thread_equal (self, mutex->owner))
- {
- mutex->depth += depth;
- return;
- }
- g_static_mutex_lock (&mutex->mutex);
- g_system_thread_assign (mutex->owner, self);
- mutex->depth = depth;
+ g_atomic_pointer_set (value_location, result);
+ 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);
}
-guint
-g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
-{
- guint depth;
-
- g_return_val_if_fail (mutex, 0);
-
- if (!g_thread_supported ())
- return 1;
+/* GThread {{{1 -------------------------------------------------------- */
- depth = mutex->depth;
+/**
+ * g_thread_ref:
+ * @thread: a #GThread
+ *
+ * Increase the reference count on @thread.
+ *
+ * Returns: a new reference to @thread
+ *
+ * Since: 2.32
+ */
+GThread *
+g_thread_ref (GThread *thread)
+{
+ GRealThread *real = (GRealThread *) thread;
- g_system_thread_assign (mutex->owner, zero_thread);
- mutex->depth = 0;
- g_static_mutex_unlock (&mutex->mutex);
+ g_atomic_int_inc (&real->ref_count);
- return depth;
+ return thread;
}
+/**
+ * g_thread_unref:
+ * @thread: a #GThread
+ *
+ * Decrease the reference count on @thread, possibly freeing all
+ * resources associated with it.
+ *
+ * Note that each thread holds a reference to its #GThread while
+ * it is running, so it is safe to drop your own reference to it
+ * if you don't need it anymore.
+ *
+ * Since: 2.32
+ */
void
-g_static_rec_mutex_free (GStaticRecMutex *mutex)
+g_thread_unref (GThread *thread)
{
- g_return_if_fail (mutex);
+ GRealThread *real = (GRealThread *) thread;
- g_static_mutex_free (&mutex->mutex);
+ if (g_atomic_int_dec_and_test (&real->ref_count))
+ {
+ if (real->ours)
+ g_system_thread_free (real);
+ else
+ g_slice_free (GRealThread, real);
+ }
}
-void
-g_static_private_init (GStaticPrivate *private_key)
+static void
+g_thread_cleanup (gpointer data)
{
- private_key->index = 0;
+ g_thread_unref (data);
}
gpointer
-g_static_private_get (GStaticPrivate *private_key)
+g_thread_proxy (gpointer data)
{
- GRealThread *self = (GRealThread*) g_thread_self ();
- GArray *array;
-
- 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;
-}
-
-void
-g_static_private_set (GStaticPrivate *private_key,
- gpointer data,
- GDestroyNotify notify)
-{
- GRealThread *self = (GRealThread*) g_thread_self ();
- GArray *array;
- static guint next_index = 0;
- GStaticPrivateNode *node;
+ GRealThread* thread = data;
- array = self->private_data;
- if (!array)
- {
- array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
- self->private_data = array;
- }
+ g_assert (data);
- if (!private_key->index)
- {
- G_LOCK (g_thread);
-
- if (!private_key->index)
- {
- if (g_thread_free_indeces)
- {
- 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);
- }
- else
- private_key->index = ++next_index;
- }
-
- G_UNLOCK (g_thread);
- }
+ /* This has to happen before G_LOCK, as that might call g_thread_self */
+ g_private_set (&g_thread_specific_private, data);
- if (private_key->index > array->len)
- g_array_set_size (array, private_key->index);
+ /* The lock makes sure that g_thread_new_internal() has a chance to
+ * setup 'func' and 'data' before we make the call.
+ */
+ G_LOCK (g_thread_new);
+ G_UNLOCK (g_thread_new);
- node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
- if (node->destroy)
+ if (thread->name)
{
- gpointer ddata = node->data;
- GDestroyNotify ddestroy = node->destroy;
+ g_system_thread_set_name (thread->name);
+ g_free (thread->name);
+ thread->name = NULL;
+ }
- node->data = data;
- node->destroy = notify;
+ thread->retval = thread->thread.func (thread->thread.data);
- ddestroy (ddata);
- }
- else
- {
- node->data = data;
- node->destroy = notify;
- }
+ return NULL;
}
-void
-g_static_private_free (GStaticPrivate *private_key)
+/**
+ * g_thread_new:
+ * @name: (allow-none): an (optional) name for the new thread
+ * @func: a function to execute in the new thread
+ * @data: an argument to supply to the new thread
+ *
+ * This function creates a new thread. The new thread starts by invoking
+ * @func with the argument data. The thread will run until @func returns
+ * or until g_thread_exit() is called from the new thread. The return value
+ * of @func becomes the return value of the thread, which can be obtained
+ * with g_thread_join().
+ *
+ * The @name can be useful for discriminating threads in a debugger.
+ * It is not used for other purposes and does not have to be unique.
+ * Some systems restrict the length of @name to 16 bytes.
+ *
+ * If the thread can not be created the program aborts. See
+ * g_thread_try_new() if you want to attempt to deal with failures.
+ *
+ * To free the struct returned by this function, use g_thread_unref().
+ * Note that g_thread_join() implicitly unrefs the #GThread as well.
+ *
+ * Returns: the new #GThread
+ *
+ * Since: 2.32
+ */
+GThread *
+g_thread_new (const gchar *name,
+ GThreadFunc func,
+ gpointer data)
{
- guint index = private_key->index;
- GSList *list;
+ GError *error = NULL;
+ GThread *thread;
- if (!index)
- return;
-
- private_key->index = 0;
+ thread = g_thread_new_internal (name, g_thread_proxy, func, data, 0, &error);
- G_LOCK (g_thread);
- list = g_thread_all_threads;
- while (list)
- {
- GRealThread *thread = list->data;
- GArray *array = thread->private_data;
- list = list->next;
-
- if (array && index <= array->len)
- {
- GStaticPrivateNode *node = &g_array_index (array,
- GStaticPrivateNode,
- index - 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);
- }
- }
- }
- g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
- GUINT_TO_POINTER (index));
- G_UNLOCK (g_thread);
-}
+ if G_UNLIKELY (thread == NULL)
+ g_error ("creating thread '%s': %s", name ? name : "", error->message);
-static void
-g_thread_cleanup (gpointer data)
-{
- if (data)
- {
- GRealThread* thread = data;
- if (thread->private_data)
- {
- GArray* array = thread->private_data;
- guint i;
-
- for (i = 0; i < array->len; i++ )
- {
- GStaticPrivateNode *node =
- &g_array_index (array, GStaticPrivateNode, i);
- if (node->destroy)
- node->destroy (node->data);
- }
- g_array_free (array, TRUE);
- }
-
- /* We only free the thread structure, if it isn't joinable. If
- it is, the structure is freed in g_thread_join */
- if (!thread->thread.joinable)
- {
- G_LOCK (g_thread);
- g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
- 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);
- }
- }
+ return thread;
}
-static void
-g_thread_fail (void)
+/**
+ * g_thread_try_new:
+ * @name: (allow-none): an (optional) name for the new thread
+ * @func: a function to execute in the new thread
+ * @data: an argument to supply to the new thread
+ * @error: return location for error, or %NULL
+ *
+ * This function is the same as g_thread_new() except that
+ * it allows for the possibility of failure.
+ *
+ * If a thread can not be created (due to resource limits),
+ * @error is set and %NULL is returned.
+ *
+ * Returns: the new #GThread, or %NULL if an error occurred
+ *
+ * Since: 2.32
+ */
+GThread *
+g_thread_try_new (const gchar *name,
+ GThreadFunc func,
+ gpointer data,
+ GError **error)
{
- g_error ("The thread system is not yet initialized.");
+ return g_thread_new_internal (name, g_thread_proxy, func, data, 0, error);
}
-static gpointer
-g_thread_create_proxy (gpointer data)
+GThread *
+g_thread_new_internal (const gchar *name,
+ GThreadFunc proxy,
+ GThreadFunc func,
+ gpointer data,
+ gsize stack_size,
+ GError **error)
{
- GRealThread* thread = data;
+ GRealThread *thread;
- g_assert (data);
-
- /* This has to happen before G_LOCK, as that might call g_thread_self */
- g_private_set (g_thread_specific_private, data);
+ g_return_val_if_fail (func != NULL, NULL);
- /* the lock makes sure, that thread->system_thread is written,
- 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)
-{
- 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->thread.joinable = joinable;
- result->thread.priority = priority;
- result->thread.func = func;
- result->thread.data = data;
- result->private_data = NULL;
- G_LOCK (g_thread);
- 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);
- G_UNLOCK (g_thread);
-
- if (local_error)
+ G_LOCK (g_thread_new);
+ thread = g_system_thread_new (proxy, stack_size, error);
+ if (thread)
{
- g_propagate_error (error, local_error);
- g_free (result);
- return NULL;
+ thread->ref_count = 2;
+ thread->ours = TRUE;
+ thread->thread.joinable = TRUE;
+ thread->thread.func = func;
+ thread->thread.data = data;
+ thread->name = g_strdup (name);
}
+ G_UNLOCK (g_thread_new);
- return (GThread*) result;
+ return (GThread*) thread;
}
+/**
+ * g_thread_exit:
+ * @retval: the return value of this thread
+ *
+ * Terminates the current thread.
+ *
+ * If another thread is waiting for us using g_thread_join() then the
+ * waiting thread will be woken up and get @retval as the return value
+ * of g_thread_join().
+ *
+ * Calling g_thread_exit() with a parameter @retval is equivalent to
+ * returning @retval from the function @func, as given to g_thread_new().
+ *
+ * You must only call g_thread_exit() from a thread that you created
+ * yourself with g_thread_new() or related APIs. You must not call
+ * this function from a thread created with another threading library
+ * or or from within a #GThreadPool.
+ */
void
g_thread_exit (gpointer retval)
{
GRealThread* real = (GRealThread*) g_thread_self ();
+
+ if G_UNLIKELY (!real->ours)
+ g_error ("attempt to g_thread_exit() a thread not created by GLib");
+
real->retval = retval;
- G_THREAD_CF (thread_exit, (void)0, ());
+
+ g_system_thread_exit ();
}
+/**
+ * g_thread_join:
+ * @thread: a #GThread
+ *
+ * Waits until @thread finishes, i.e. the function @func, as
+ * given to g_thread_new(), returns or g_thread_exit() is called.
+ * If @thread has already terminated, then g_thread_join()
+ * returns immediately.
+ *
+ * Any thread can wait for any other thread by calling g_thread_join(),
+ * not just its 'creator'. Calling g_thread_join() from multiple threads
+ * for the same @thread leads to undefined behaviour.
+ *
+ * The value returned by @func or given to g_thread_exit() is
+ * returned by this function.
+ *
+ * g_thread_join() consumes the reference to the passed-in @thread.
+ * This will usually cause the #GThread struct and associated resources
+ * to be freed. Use g_thread_ref() to obtain an extra reference if you
+ * want to keep the GThread alive beyond the g_thread_join() call.
+ *
+ * Returns: the return value of the thread
+ */
gpointer
-g_thread_join (GThread* thread)
+g_thread_join (GThread *thread)
{
- GRealThread* real = (GRealThread*) thread;
+ GRealThread *real = (GRealThread*) thread;
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,
- zero_thread), NULL);
+ g_return_val_if_fail (real->ours, NULL);
- G_THREAD_UF (thread_join, (&real->system_thread));
+ g_system_thread_wait (real);
retval = real->retval;
- G_LOCK (g_thread);
- g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
- G_UNLOCK (g_thread);
-
/* Just to make sure, this isn't used any more */
thread->joinable = 0;
- g_system_thread_assign (real->system_thread, zero_thread);
- /* the thread structure for non-joinable threads is freed upon
- thread end. We free the memory here. This will leave a loose end,
- if a joinable thread is not joined. */
-
- g_free (thread);
+ g_thread_unref (thread);
return retval;
}
-void
-g_thread_set_priority (GThread* thread,
- GThreadPriority priority)
-{
- GRealThread* real = (GRealThread*) thread;
-
- g_return_if_fail (thread);
- g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
- g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
- g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
-
- thread->priority = priority;
-
- G_THREAD_CF (thread_set_priority, (void)0,
- (&real->system_thread, priority));
-}
-
+/**
+ * g_thread_self:
+ *
+ * This functions returns the #GThread corresponding to the
+ * current thread. Note that this function does not increase
+ * the reference count of the returned struct.
+ *
+ * This function will return a #GThread even for threads that
+ * were not created by GLib (i.e. those created by other threading
+ * APIs). This may be useful for thread identification purposes
+ * (i.e. comparisons) but you must not use GLib functions (such
+ * as g_thread_join()) on these threads.
+ *
+ * Returns: the #GThread representing the current thread
+ */
GThread*
g_thread_self (void)
{
- GRealThread* thread = g_private_get (g_thread_specific_private);
+ 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->thread.joinable = FALSE; /* This is a save guess */
- thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
- just a guess */
- thread->thread.func = NULL;
- thread->thread.data = NULL;
- thread->private_data = NULL;
-
- if (g_thread_supported ())
- G_THREAD_UF (thread_self, (&thread->system_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);
- G_UNLOCK (g_thread);
- }
-
- return (GThread*)thread;
-}
-
-void
-g_static_rw_lock_init (GStaticRWLock* lock)
-{
- static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
-
- g_return_if_fail (lock);
-
- *lock = init_lock;
-}
-
-static void inline
-g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
-{
- if (!*cond)
- *cond = g_cond_new ();
- g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
-}
-
-static void inline
-g_static_rw_lock_signal (GStaticRWLock* lock)
-{
- if (lock->want_to_write && lock->write_cond)
- g_cond_signal (lock->write_cond);
- else if (lock->want_to_read && lock->read_cond)
- g_cond_broadcast (lock->read_cond);
-}
-
-void
-g_static_rw_lock_reader_lock (GStaticRWLock* lock)
-{
- g_return_if_fail (lock);
-
- if (!g_threads_got_initialized)
- return;
-
- g_static_mutex_lock (&lock->mutex);
- lock->want_to_read++;
- 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 (GStaticRWLock* lock)
-{
- gboolean ret_val = FALSE;
-
- g_return_val_if_fail (lock, FALSE);
-
- if (!g_threads_got_initialized)
- return TRUE;
-
- g_static_mutex_lock (&lock->mutex);
- if (!lock->have_writer && !lock->want_to_write)
{
- lock->read_counter++;
- ret_val = TRUE;
+ /* 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_slice_new0 (GRealThread);
+ thread->ref_count = 1;
+
+ g_private_set (&g_thread_specific_private, thread);
}
- g_static_mutex_unlock (&lock->mutex);
- return ret_val;
-}
-
-void
-g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
-{
- g_return_if_fail (lock);
- if (!g_threads_got_initialized)
- return;
-
- g_static_mutex_lock (&lock->mutex);
- lock->read_counter--;
- if (lock->read_counter == 0)
- g_static_rw_lock_signal (lock);
- g_static_mutex_unlock (&lock->mutex);
+ return (GThread*) thread;
}
-void
-g_static_rw_lock_writer_lock (GStaticRWLock* lock)
-{
- g_return_if_fail (lock);
-
- if (!g_threads_got_initialized)
- return;
-
- g_static_mutex_lock (&lock->mutex);
- lock->want_to_write++;
- while (lock->have_writer || lock->read_counter)
- g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
- lock->want_to_write--;
- lock->have_writer = TRUE;
- g_static_mutex_unlock (&lock->mutex);
-}
-
-gboolean
-g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
+/**
+ * g_get_num_processors:
+ *
+ * Determine the approximate number of threads that the system will
+ * schedule simultaneously for this process. This is intended to be
+ * used as a parameter to g_thread_pool_new() for CPU bound tasks and
+ * similar cases.
+ *
+ * Returns: Number of schedulable threads, always greater than 0
+ *
+ * Since: 2.36
+ */
+guint
+g_get_num_processors (void)
{
- gboolean ret_val = FALSE;
-
- g_return_val_if_fail (lock, FALSE);
-
- if (!g_threads_got_initialized)
- return TRUE;
+#ifdef G_OS_WIN32
+ DWORD_PTR process_cpus;
+ DWORD_PTR system_cpus;
- g_static_mutex_lock (&lock->mutex);
- if (!lock->have_writer && !lock->read_counter)
+ if (GetProcessAffinityMask (GetCurrentProcess (),
+ &process_cpus, &system_cpus))
{
- lock->have_writer = TRUE;
- ret_val = TRUE;
- }
- g_static_mutex_unlock (&lock->mutex);
- return ret_val;
-}
+ unsigned int count;
-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;
- g_static_rw_lock_signal (lock);
- g_static_mutex_unlock (&lock->mutex);
-}
+ for (count = 0; process_cpus != 0; process_cpus >>= 1)
+ if (process_cpus & 1)
+ count++;
-void
-g_static_rw_lock_free (GStaticRWLock* lock)
-{
- g_return_if_fail (lock);
-
- if (lock->read_cond)
- {
- g_cond_free (lock->read_cond);
- lock->read_cond = NULL;
+ if (count > 0)
+ return count;
}
- if (lock->write_cond)
- {
- g_cond_free (lock->write_cond);
- lock->write_cond = NULL;
- }
- g_static_mutex_free (&lock->mutex);
+#elif defined(_SC_NPROCESSORS_ONLN)
+ {
+ int count;
+
+ count = sysconf (_SC_NPROCESSORS_ONLN);
+ if (count > 0)
+ return count;
+ }
+#elif defined HW_NCPU
+ {
+ int mib[2], count = 0;
+ size_t len;
+
+ mib[0] = CTL_HW;
+ mib[1] = HW_NCPU;
+ len = sizeof(count);
+
+ if (sysctl (mib, 2, &count, &len, NULL, 0) == 0 && count > 0)
+ return count;
+ }
+#endif
+
+ return 1; /* Fallback */
}
-#define __G_THREAD_C__
-#include "galiasdef.c"
+/* Epilogue {{{1 */
+/* vim: set foldmethod=marker: */
projects / platform / upstream / glib.git / blobdiff