* 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 ----------------------------------------------------------- */
#include <string.h>
-#ifdef HAVE_UNISTD_H
+#ifdef G_OS_UNIX
#include <unistd.h>
#endif
#endif /* G_OS_WIN32 */
#include "gslice.h"
+#include "gstrfuncs.h"
#include "gtestutils.h"
/**
* (#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).
+ * 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. It is still possible to do thread-unsafe
- * initialization and setup at the beginning of your program, before
- * creating the first threads.
- *
- * GLib is internally completely thread-safe (all global data is
+ * 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 <emphasis>are</emphasis> 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.
+ * 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.
*/
/* G_LOCK Documentation {{{1 ---------------------------------------------- */
* G_LOCK_DEFINE:
* @name: the name of the lock
*
- * The %G_LOCK_* macros provide a convenient interface to #GMutex.
+ * 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
- * <function>give_me_next_number()</function> example using the
- * %G_LOCK_* macros:
+ * give_me_next_number() example using the #G_LOCK macros:
*
- * <example>
- * <title>Using the %G_LOCK_* convenience macros</title>
- * <programlisting>
+ * Here is an example for using the #G_LOCK convenience macros:
+ * |[<!-- language="C" -->
* G_LOCK_DEFINE (current_number);
*
* int
*
* return ret_val;
* }
- * </programlisting>
- * </example>
+ * ]|
*/
/**
/**
* 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.
+ *
+ * Returns: %TRUE, if the lock could be locked.
*/
/**
*
* 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:
+ * access.
*
- * <example>
- * <title>A function which will not work in a threaded environment</title>
- * <programlisting>
+ * 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
- * *<!-- -->/
+ * // 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 #GMutex can be used as a solution to this problem:
- *
- * <example>
- * <title>Using GMutex to protected a shared variable</title>
- * <programlisting>
+ * |[<!-- language="C" -->
* int
* give_me_next_number (void)
* {
* static int current_number = 0;
* int ret_val;
*
- * g_mutex_lock (&mutex);
+ * g_mutex_lock (&mutex);
* ret_val = current_number = calc_next_number (current_number);
- * g_mutex_unlock (&mutex);
+ * g_mutex_unlock (&mutex);
*
* return ret_val;
* }
- * </programlisting>
- * </example>
- *
+ * ]|
* 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 <function>g_mutex_</function>
- * functions.
+ * A #GMutex should only be accessed via g_mutex_ functions.
*/
/* GRecMutex Documentation {{{1 -------------------------------------- */
* g_rec_mutex_init() on it and g_rec_mutex_clear() when done.
*
* A GRecMutex should only be accessed with the
- * <function>g_rec_mutex_</function> functions.
+ * g_rec_mutex_ functions.
*
* Since: 2.32
*/
* simultaneous read-only access (by holding the 'reader' lock via
* g_rw_lock_reader_lock()).
*
- * <example>
- * <title>An array with access functions</title>
- * <programlisting>
+ * Here is an example for an array with access functions:
+ * |[<!-- language="C" -->
* GRWLock lock;
* GPtrArray *array;
*
* if (!array)
* return NULL;
*
- * g_rw_lock_reader_lock (&lock);
- * if (index < array->len)
+ * g_rw_lock_reader_lock (&lock);
+ * if (index < array->len)
* retval = g_ptr_array_index (array, index);
- * g_rw_lock_reader_unlock (&lock);
+ * g_rw_lock_reader_unlock (&lock);
*
* return retval;
* }
* void
* my_array_set (guint index, gpointer data)
* {
- * g_rw_lock_writer_lock (&lock);
+ * g_rw_lock_writer_lock (&lock);
*
* if (!array)
- * array = g_ptr_array_new (<!-- -->);
+ * 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);
+ * g_rw_lock_writer_unlock (&lock);
* }
- * </programlisting>
- * <para>
- * 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.
- * </para>
- * </example>
+ * ]|
+ * 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
- * <function>g_rw_lock_</function> functions.
+ * A GRWLock should only be accessed with the g_rw_lock_ functions.
*
* Since: 2.32
*/
* 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 *<!-- -->/
+ * 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);
+ * g_mutex_lock (&data_mutex);
* current_data = data;
- * g_cond_signal (data_cond);
- * g_mutex_unlock (data_mutex);
+ * g_cond_signal (&data_cond);
+ * g_mutex_unlock (&data_mutex);
* }
*
* gpointer
* {
* gpointer data;
*
- * g_mutex_lock (data_mutex);
+ * g_mutex_lock (&data_mutex);
* while (!current_data)
- * g_cond_wait (data_cond, data_mutex);
+ * g_cond_wait (&data_cond, &data_mutex);
* data = current_data;
* current_data = NULL;
- * g_mutex_unlock (data_mutex);
+ * g_mutex_unlock (&data_mutex);
*
* return data;
* }
- * </programlisting>
- * </example>
- *
+ * ]|
* 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().
*
- * <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>
+ * 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.
+ * 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 <function>g_cond_</function>
- * functions.
+ * A #GCond should only be accessed via the g_cond_ functions.
*/
/* GThread Documentation {{{1 ---------------------------------------- */
* GThread:
*
* The #GThread struct represents a running thread. This struct
- * is returned by g_thread_new() or g_thread_new_full(). You can
- * obtain the #GThread struct representing the current thead by
+ * 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.
*/
* GThreadFunc:
* @data: data passed to the thread
*
- * Specifies the type of the @func functions passed to
- * g_thread_new() or g_thread_new_full().
- *
- * If the thread is joinable, the return value of this function
- * is returned by a g_thread_join() call waiting for the thread.
- * If the thread is not joinable, the return value is ignored.
+ * Specifies the type of the @func functions passed to g_thread_new()
+ * or g_thread_try_new().
*
* Returns: the return value of the thread
*/
*
* The error domain of the GLib thread subsystem.
**/
-GQuark
-g_thread_error_quark (void)
-{
- return g_quark_from_static_string ("g_thread_error");
-}
+G_DEFINE_QUARK (g_thread_error, g_thread_error)
/* Local Data {{{1 -------------------------------------------------------- */
-GMutex g_once_mutex;
+static GMutex g_once_mutex;
static GCond g_once_cond;
static GSList *g_once_init_list = NULL;
*
* A #GOnce must be initialized with this macro before it can be used.
*
- * |[
+ * |[<!-- language="C" -->
* GOnce my_once = G_ONCE_INIT;
* ]|
*
* Calling g_once() recursively on the same #GOnce struct in
* @func will lead to a deadlock.
*
- * |[
+ * |[<!-- language="C" -->
* gpointer
* get_debug_flags (void)
* {
/**
* g_once_init_enter:
- * @value_location: location of a static initializable variable
- * containing 0
+ * @location: location of a static initializable variable containing 0
*
* Function to be called when starting a critical initialization
- * section. The argument @value_location must point to a static
+ * 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
* 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))
+ * if (g_once_init_enter (&initialization_value))
* {
- * gsize setup_value = 42; /** initialization code here **/
+ * gsize setup_value = 42; // initialization code here
*
- * g_once_init_leave (&initialization_value, setup_value);
+ * g_once_init_leave (&initialization_value, setup_value);
* }
*
- * /** use initialization_value here **/
+ * // use initialization_value here
* ]|
*
* Returns: %TRUE if the initialization section should be entered,
* Since: 2.14
*/
gboolean
-(g_once_init_enter) (volatile void *pointer)
+(g_once_init_enter) (volatile void *location)
{
- volatile gsize *value_location = pointer;
+ volatile gsize *value_location = location;
gboolean need_init = FALSE;
g_mutex_lock (&g_once_mutex);
if (g_atomic_pointer_get (value_location) == NULL)
/**
* g_once_init_leave:
- * @value_location: location of a static initializable variable
- * containing 0
+ * @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
* Since: 2.14
*/
void
-(g_once_init_leave) (volatile void *pointer,
+(g_once_init_leave) (volatile void *location,
gsize result)
{
- volatile gsize *value_location = pointer;
+ volatile gsize *value_location = location;
g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
g_return_if_fail (result != 0);
/* GThread {{{1 -------------------------------------------------------- */
-static void
-g_thread_cleanup (gpointer data)
+/**
+ * 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)
{
- if (data)
- {
- GRealThread* thread = data;
+ GRealThread *real = (GRealThread *) thread;
- /* 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)
- {
- /* Just to make sure, this isn't used any more */
- g_system_thread_assign (thread->system_thread, zero_thread);
- g_free (thread);
- }
+ g_atomic_int_inc (&real->ref_count);
+
+ 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_thread_unref (GThread *thread)
+{
+ GRealThread *real = (GRealThread *) thread;
+
+ if (g_atomic_int_dec_and_test (&real->ref_count))
+ {
+ if (real->ours)
+ g_system_thread_free (real);
+ else
+ g_slice_free (GRealThread, real);
}
}
-static gpointer
-g_thread_create_proxy (gpointer data)
+static void
+g_thread_cleanup (gpointer data)
+{
+ g_thread_unref (data);
+}
+
+gpointer
+g_thread_proxy (gpointer data)
{
GRealThread* thread = data;
g_assert (data);
- if (thread->name)
- g_system_thread_set_name (thread->name);
-
/* This has to happen before G_LOCK, as that might call g_thread_self */
g_private_set (&g_thread_specific_private, data);
- if (thread->enumerable)
- g_enumerable_thread_add (thread);
-
- /* The lock makes sure that thread->system_thread is written,
- * before thread->thread.func is called. See g_thread_new_internal().
+ /* 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);
+ if (thread->name)
+ {
+ g_system_thread_set_name (thread->name);
+ g_free (thread->name);
+ thread->name = NULL;
+ }
+
thread->retval = thread->thread.func (thread->thread.data);
return NULL;
/**
* g_thread_new:
- * @name: a name for the new thread
+ * @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
- * @joinable: should this thread be joinable?
- * @error: return location for error
*
* 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.
+ * 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. Some systems restrict the length of @name to
- * 16 bytes.
+ * 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 @joinable is %TRUE, you can wait for this thread's termination
- * calling g_thread_join(). Resources for a joinable thread are not
- * fully released until g_thread_join() is called for that thread.
- * Otherwise the thread will just disappear when it terminates.
+ * If the thread can not be created the program aborts. See
+ * g_thread_try_new() if you want to attempt to deal with failures.
*
- * @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.
+ * 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, or %NULL if an error occurred
+ * Returns: the new #GThread
*
* Since: 2.32
*/
GThread *
-g_thread_new (const gchar *name,
- GThreadFunc func,
- gpointer data,
- gboolean joinable,
- GError **error)
+g_thread_new (const gchar *name,
+ GThreadFunc func,
+ gpointer data)
{
- return g_thread_new_internal (name, func, data, joinable, 0, FALSE, error);
+ GError *error = NULL;
+ GThread *thread;
+
+ thread = g_thread_new_internal (name, g_thread_proxy, func, data, 0, &error);
+
+ if G_UNLIKELY (thread == NULL)
+ g_error ("creating thread '%s': %s", name ? name : "", error->message);
+
+ return thread;
}
/**
- * g_thread_new_full:
- * @name: a name for the new thread
+ * 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
- * @joinable: should this thread be joinable?
- * @stack_size: a stack size for the new thread
- * @error: return location for error
- *
- * 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.
+ * @error: return location for error, or %NULL
*
- * The @name can be useful for discriminating threads in
- * a debugger. Some systems restrict the length of @name to
- * 16 bytes.
+ * This function is the same as g_thread_new() except that
+ * it allows for the possibility of failure.
*
- * 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. Note that you should only
- * use a non-zero @stack_size if you really can't use the default.
- * In most cases, using g_thread_new() (which doesn't take a
- * @stack_size) is better.
- *
- * If @joinable is %TRUE, you can wait for this thread's termination
- * calling g_thread_join(). Resources for a joinable thread are not
- * fully released until g_thread_join() is called for that thread.
- * Otherwise the thread will just disappear when it terminates.
- *
- * @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.
+ * 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_new_full (const gchar *name,
- GThreadFunc func,
- gpointer data,
- gboolean joinable,
- gsize stack_size,
- GError **error)
+g_thread_try_new (const gchar *name,
+ GThreadFunc func,
+ gpointer data,
+ GError **error)
{
- return g_thread_new_internal (name, func, data, joinable, stack_size, FALSE, error);
+ return g_thread_new_internal (name, g_thread_proxy, func, data, 0, error);
}
GThread *
-g_thread_new_internal (const gchar *name,
- GThreadFunc func,
- gpointer data,
- gboolean joinable,
- gsize stack_size,
- gboolean enumerable,
- GError **error)
+g_thread_new_internal (const gchar *name,
+ GThreadFunc proxy,
+ GThreadFunc func,
+ gpointer data,
+ gsize stack_size,
+ GError **error)
{
- GRealThread *result;
- GError *local_error = NULL;
+ GRealThread *thread;
g_return_val_if_fail (func != NULL, NULL);
- result = g_new0 (GRealThread, 1);
-
- result->thread.joinable = joinable;
- result->thread.func = func;
- result->thread.data = data;
- result->enumerable = enumerable;
- result->name = name;
G_LOCK (g_thread_new);
- g_system_thread_create (g_thread_create_proxy, result,
- stack_size, joinable,
- &result->system_thread, &local_error);
- G_UNLOCK (g_thread_new);
-
- if (local_error)
+ 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;
}
/**
*
* Terminates 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.
+ * 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 <literal>g_thread_exit (retval)</literal> is equivalent to
+ * Calling g_thread_exit() with a parameter @retval is equivalent to
* returning @retval from the function @func, as given to g_thread_new().
*
- * <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>
+ * 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_system_thread_exit ();
/**
* g_thread_join:
- * @thread: a joinable #GThread
+ * @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. @thread must be joinable.
+ * returns immediately.
*
- * Any thread can wait for any other (joinable) 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.
+ * 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.
*
- * All resources of @thread including the #GThread struct are
- * released before g_thread_join() returns.
+ * 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 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_system_thread_join (&real->system_thread);
+ g_system_thread_wait (real);
retval = real->retval;
/* 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;
}
* g_thread_self:
*
* This functions returns the #GThread corresponding to the
- * current thread.
+ * 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
*/
* This can happen for the main thread and for threads
* that are not created by GLib.
*/
- thread = g_new0 (GRealThread, 1);
- thread->thread.joinable = FALSE; /* This is a safe guess */
- thread->thread.func = NULL;
- thread->thread.data = NULL;
- thread->enumerable = FALSE;
-
- g_system_thread_self (&thread->system_thread);
+ thread = g_slice_new0 (GRealThread);
+ thread->ref_count = 1;
g_private_set (&g_thread_specific_private, thread);
}
- return (GThread*)thread;
+ return (GThread*) thread;
+}
+
+/**
+ * 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)
+{
+#ifdef G_OS_WIN32
+ DWORD_PTR process_cpus;
+ DWORD_PTR system_cpus;
+
+ if (GetProcessAffinityMask (GetCurrentProcess (),
+ &process_cpus, &system_cpus))
+ {
+ unsigned int count;
+
+ for (count = 0; process_cpus != 0; process_cpus >>= 1)
+ if (process_cpus & 1)
+ count++;
+
+ if (count > 0)
+ return count;
+ }
+#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 */
}
/* Epilogue {{{1 */
projects / platform / upstream / glib.git / blobdiff