X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=glib%2Fgthread.c;h=ea8e5f9656f55945bb365f645e25dee26b61ed6b;hb=30ed5f53e205e6bfc35126a9d3c62dac8a9c5dad;hp=75ccb3e63fa462d45469e4d627a30073bdd03ba5;hpb=9d989c7b8aebda0e56aaadb843def0f48f909156;p=platform%2Fupstream%2Fglib.git diff --git a/glib/gthread.c b/glib/gthread.c index 75ccb3e..ea8e5f9 100644 --- a/glib/gthread.c +++ b/glib/gthread.c @@ -16,9 +16,7 @@ * 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 . */ /* Prelude {{{1 ----------------------------------------------------------- */ @@ -45,7 +43,7 @@ #include -#ifdef HAVE_UNISTD_H +#ifdef G_OS_UNIX #include #endif @@ -57,6 +55,7 @@ #endif /* G_OS_WIN32 */ #include "gslice.h" +#include "gstrfuncs.h" #include "gtestutils.h" /** @@ -82,43 +81,65 @@ * (#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 threading system is initialized with g_thread_init(). - * 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 do 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. Since 2.32, creating - * a mainloop will do so too. As a consequence, most applications, - * including those using GTK+, will run with threads enabled. - * - * 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 are - * threadsafe and need no further application-level locking to be - * accessed from multiple threads. - */ - -/** - * G_THREADS_IMPL_POSIX: - * - * This macro is defined if POSIX style threads are used. - */ - -/** - * G_THREADS_IMPL_WIN32: - * - * This macro is defined if Windows style threads are used. + * 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. */ /* G_LOCK Documentation {{{1 ---------------------------------------------- */ @@ -127,19 +148,17 @@ * 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 - * give_me_next_number() example using the - * %G_LOCK_* macros: + * give_me_next_number() example using the #G_LOCK macros: * - * - * Using the %G_LOCK_* convenience macros - * + * Here is an example for using the #G_LOCK convenience macros: + * |[ * G_LOCK_DEFINE (current_number); * * int @@ -154,8 +173,7 @@ * * return ret_val; * } - * - * + * ]| */ /** @@ -184,10 +202,11 @@ /** * 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. */ /** @@ -205,98 +224,26 @@ * * 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. * - * - * A function which will not work in a threaded environment - * + * Take for example the following function: + * |[ * 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; * } - * - * - * + * ]| * 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: - * - * - * The wrong way to write a thread-safe function - * - * 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; - * } - * - * - * - * 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: - * - * - * A correct thread-safe function - * - * 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; - * } - * - * - * - * If a #GMutex is allocated in static storage then it can be used - * without initialisation. Otherwise, you should call g_mutex_init() on - * it and g_mutex_clear() when done. - * - * A statically initialized #GMutex provides an even simpler and safer - * way of doing this: - * - * - * Using a statically allocated mutex - * + * access. A #GMutex can be used as a solution to this problem: + * |[ * int * give_me_next_number (void) * { @@ -304,17 +251,21 @@ * 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; * } - * - * + * ]| + * 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. + * A #GMutex should only be accessed via g_mutex_ functions. */ /* GRecMutex Documentation {{{1 -------------------------------------- */ @@ -333,7 +284,7 @@ * 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. + * g_rec_mutex_ functions. * * Since: 2.32 */ @@ -354,9 +305,8 @@ * simultaneous read-only access (by holding the 'reader' lock via * g_rw_lock_reader_lock()). * - * - * An array with access functions - * + * Here is an example for an array with access functions: + * |[ * GRWLock lock; * GPtrArray *array; * @@ -368,10 +318,10 @@ * 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; * } @@ -379,35 +329,30 @@ * 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); * } - * - * - * 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 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. - * - * + * ]| + * 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. + * A GRWLock should only be accessed with the g_rw_lock_ functions. * * Since: 2.32 */ @@ -423,22 +368,25 @@ * condition they signal the #GCond, and that causes the waiting * threads to be woken up. * - * - * - * Using GCond to block a thread until a condition is satisfied - * - * - * 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: + * |[ * 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 @@ -446,37 +394,39 @@ * { * 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; * } - * - * - * + * ]| * 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(). * - * 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. + * 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 g_cond_ - * functions. + * A #GCond should only be accessed via the g_cond_ functions. */ /* GThread Documentation {{{1 ---------------------------------------- */ @@ -485,21 +435,26 @@ * 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 */ @@ -530,18 +485,11 @@ * * 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 -------------------------------------------------------- */ -gboolean g_threads_got_initialized = FALSE; -GSystemThread zero_thread; /* This is initialized to all zero */ - -GMutex g_once_mutex; +static GMutex g_once_mutex; static GCond g_once_cond; static GSList *g_once_init_list = NULL; @@ -550,74 +498,6 @@ static GPrivate g_thread_specific_private = G_PRIVATE_INIT (g_thread_cleanup G_LOCK_DEFINE_STATIC (g_thread_new); -/* Initialisation {{{1 ---------------------------------------------------- */ - -/** - * g_thread_init: - * @vtable: a function table of type #GThreadFunctions, that provides - * the entry points to the thread system to be used. Since 2.32, - * this parameter is ignored and should always be %NULL - * - * If you use GLib from more than one thread, you must initialize the - * thread system by calling g_thread_init(). - * - * Since version 2.24, calling g_thread_init() multiple times is allowed, - * but nothing happens except for the first call. - * - * Since version 2.32, GLib does not support custom thread implementations - * anymore and the @vtable parameter is ignored and you should pass %NULL. - * - * g_thread_init() must not be called directly or indirectly - * in a callback from GLib. Also no mutexes may be currently locked while - * calling g_thread_init(). - * - * To use g_thread_init() in your program, you have to link - * with the libraries that the command pkg-config --libs - * gthread-2.0 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. - */ - -void -g_thread_init_glib (void) -{ - static gboolean already_done; - GRealThread *main_thread; - - if (already_done) - return; - - already_done = TRUE; - - /* We let the main thread (the one that calls g_thread_init) inherit - * the static_private data set before calling g_thread_init - */ - main_thread = (GRealThread*) g_thread_self (); - - /* setup the basic threading system */ - g_threads_got_initialized = TRUE; - g_private_set (&g_thread_specific_private, main_thread); - g_system_thread_self (&main_thread->system_thread); - - /* accomplish log system initialization to enable messaging */ - _g_messages_thread_init_nomessage (); -} - -/** - * 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 (void) -{ - return g_thread_supported (); -} - /* GOnce {{{1 ------------------------------------------------------------- */ /** @@ -638,7 +518,7 @@ g_thread_get_initialized (void) * * A #GOnce must be initialized with this macro before it can be used. * - * |[ + * |[ * GOnce my_once = G_ONCE_INIT; * ]| * @@ -678,7 +558,7 @@ g_thread_get_initialized (void) * Calling g_once() recursively on the same #GOnce struct in * @func will lead to a deadlock. * - * |[ + * |[ * gpointer * get_debug_flags (void) * { @@ -721,11 +601,10 @@ g_once_impl (GOnce *once, /** * 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 @@ -734,17 +613,17 @@ g_once_impl (GOnce *once, * blocked until initialization completed. To be used in constructs * like this: * - * |[ + * |[ * 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, @@ -753,8 +632,9 @@ g_once_impl (GOnce *once, * Since: 2.14 */ gboolean -g_once_init_enter_impl (volatile gsize *value_location) +(g_once_init_enter) (volatile void *location) { + volatile gsize *value_location = location; gboolean need_init = FALSE; g_mutex_lock (&g_once_mutex); if (g_atomic_pointer_get (value_location) == NULL) @@ -775,9 +655,8 @@ g_once_init_enter_impl (volatile gsize *value_location) /** * g_once_init_leave: - * @value_location: location of a static initializable variable - * containing 0 - * @initialization_value: new non-0 value for *@value_location + * @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 @@ -788,14 +667,16 @@ g_once_init_enter_impl (volatile gsize *value_location) * Since: 2.14 */ void -g_once_init_leave (volatile gsize *value_location, - gsize initialization_value) +(g_once_init_leave) (volatile void *location, + gsize result) { + volatile gsize *value_location = location; + g_return_if_fail (g_atomic_pointer_get (value_location) == NULL); - g_return_if_fail (initialization_value != 0); + g_return_if_fail (result != 0); g_return_if_fail (g_once_init_list != NULL); - g_atomic_pointer_set (value_location, initialization_value); + 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); @@ -804,49 +685,82 @@ g_once_init_leave (volatile gsize *value_location, /* 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; - g_static_private_cleanup (thread); + g_atomic_int_inc (&real->ref_count); - /* 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) - { - if (thread->enumerable) - g_enumerable_thread_remove (thread); + return thread; +} - /* Just to make sure, this isn't used any more */ - g_system_thread_assign (thread->system_thread, zero_thread); - g_free (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); - /* 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; @@ -854,127 +768,98 @@ g_thread_create_proxy (gpointer data) /** * 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. + * 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. 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 threads 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 + * @error: return location for error, or %NULL * - * 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. + * This function is the same as g_thread_new() except that + * it allows for the possibility of failure. * - * The @name can be useful for discriminating threads in - * a debugger. Some systems restrict the length of @name to - * 16 bytes. - * - * 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 threads 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->private_data = NULL; - 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); - if (enumerable && !local_error) - g_enumerable_thread_add (result); - 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; } /** @@ -983,22 +868,26 @@ g_thread_new_internal (const gchar *name, * * 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 g_thread_exit (retval) 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(). * - * 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. + * 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 (); @@ -1006,23 +895,24 @@ g_thread_exit (gpointer retval) /** * 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 */ @@ -1033,25 +923,16 @@ g_thread_join (GThread *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; - if (real->enumerable) - g_enumerable_thread_remove (real); - /* 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; } @@ -1060,7 +941,14 @@ g_thread_join (GThread *thread) * 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 */ @@ -1075,91 +963,69 @@ g_thread_self (void) * 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->private_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; } -/* GMutex {{{1 ------------------------------------------------------ */ - /** - * g_mutex_new: - * - * Allocates and initializes a new #GMutex. + * g_get_num_processors: * - * Returns: a newly allocated #GMutex. Use g_mutex_free() to free - */ -GMutex * -g_mutex_new (void) -{ - GMutex *mutex; - - mutex = g_slice_new (GMutex); - g_mutex_init (mutex); - - return mutex; -} - -/** - * g_mutex_free: - * @mutex: a #GMutex + * 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. * - * Destroys a @mutex that has been created with g_mutex_new(). + * Returns: Number of schedulable threads, always greater than 0 * - * Calling g_mutex_free() on a locked mutex may result - * in undefined behaviour. + * Since: 2.36 */ -void -g_mutex_free (GMutex *mutex) +guint +g_get_num_processors (void) { - g_mutex_clear (mutex); - g_slice_free (GMutex, mutex); -} - -/* GCond {{{1 ------------------------------------------------------ */ +#ifdef G_OS_WIN32 + DWORD_PTR process_cpus; + DWORD_PTR system_cpus; -/** - * g_cond_new: - * - * Allocates and initializes a new #GCond. - * - * Returns: a newly allocated #GCond. Free with g_cond_free() - */ -GCond * -g_cond_new (void) -{ - GCond *cond; + if (GetProcessAffinityMask (GetCurrentProcess (), + &process_cpus, &system_cpus)) + { + unsigned int count; - cond = g_slice_new (GCond); - g_cond_init (cond); + for (count = 0; process_cpus != 0; process_cpus >>= 1) + if (process_cpus & 1) + count++; - return cond; -} + 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 -/** - * g_cond_free: - * @cond: a #GCond - * - * Destroys a #GCond that has been created with g_cond_new(). - * - * Calling g_cond_free() for a #GCond on which threads are - * blocking leads to undefined behaviour. - */ -void -g_cond_free (GCond *cond) -{ - g_cond_clear (cond); - g_slice_free (GCond, cond); + return 1; /* Fallback */ } /* Epilogue {{{1 */