Creates a new #GMainContext structure.
Tries to become the owner of the specified context. If some other thread is the owner of the context, returns %FALSE immediately. Ownership is properly recursive: the owner can require ownership again and will release ownership when g_main_context_release() is called as many times as g_main_context_acquire().
You must be the owner of a context before you can call g_main_context_prepare(), g_main_context_query(), g_main_context_check(), g_main_context_dispatch().
Adds a file descriptor to the set of file descriptors polled for this context. This will very seldom be used directly. Instead a typical event source will use g_source_add_unix_fd() instead.
a #GPollFD structure holding information about a file descriptor to watch.
the priority for this file descriptor which should be the same as the priority used for g_source_attach() to ensure that the file descriptor is polled whenever the results may be needed.
Passes the results of polling back to the main loop. You should be
careful to pass fds and its length n_fds as received from
g_main_context_query(), as this functions relies on assumptions
on how fds is filled.
You must have successfully acquired the context with g_main_context_acquire() before you may call this function.
the maximum numerical priority of sources to check
array of #GPollFD's that was passed to the last call to g_main_context_query()
Dispatches all pending sources.
You must have successfully acquired the context with g_main_context_acquire() before you may call this function.
Finds a source with the given source functions and user data. If multiple sources exist with the same source function and user data, the first one found will be returned.
the source_funcs passed to g_source_new().
the user data from the callback.
Finds a #GSource given a pair of context and ID.
It is a programmer error to attempt to look up a non-existent source.
More specifically: source IDs can be reissued after a source has been destroyed and therefore it is never valid to use this function with a source ID which may have already been removed. An example is when scheduling an idle to run in another thread with g_idle_add(): the idle may already have run and been removed by the time this function is called on its (now invalid) source ID. This source ID may have been reissued, leading to the operation being performed against the wrong source.
the source ID, as returned by g_source_get_id().
Invokes a function in such a way that context is owned during the
invocation of function.
This function is the same as g_main_context_invoke() except that it
lets you specify the priority in case function ends up being
scheduled as an idle and also lets you give a #GDestroyNotify for data.
notify should not assume that it is called from any particular
thread or with any particular context acquired.
the priority at which to run function
function to call
Determines whether this thread holds the (recursive)
ownership of this #GMainContext. This is useful to
know before waiting on another thread that may be
blocking to get ownership of context.
Runs a single iteration for the given main loop. This involves
checking to see if any event sources are ready to be processed,
then if no events sources are ready and may_block is %TRUE, waiting
for a source to become ready, then dispatching the highest priority
events sources that are ready. Otherwise, if may_block is %FALSE
sources are not waited to become ready, only those highest priority
events sources will be dispatched (if any), that are ready at this
given moment without further waiting.
Note that even when may_block is %TRUE, it is still possible for
g_main_context_iteration() to return %FALSE, since the wait may
be interrupted for other reasons than an event source becoming ready.
whether the call may block.
Checks if any sources have pending events for the given context.
Pops context off the thread-default context stack (verifying that
it was on the top of the stack).
Prepares to poll sources within a main loop. The resulting information for polling is determined by calling g_main_context_query ().
You must have successfully acquired the context with g_main_context_acquire() before you may call this function.
Acquires context and sets it as the thread-default context for the
current thread. This will cause certain asynchronous operations
(such as most [gio][gio]-based I/O) which are
started in this thread to run under context and deliver their
results to its main loop, rather than running under the global
default context in the main thread. Note that calling this function
changes the context returned by g_main_context_get_thread_default(),
not the one returned by g_main_context_default(), so it does not affect
the context used by functions like g_idle_add().
Normally you would call this function shortly after creating a new thread, passing it a #GMainContext which will be run by a #GMainLoop in that thread, to set a new default context for all async operations in that thread. In this case you may not need to ever call g_main_context_pop_thread_default(), assuming you want the new #GMainContext to be the default for the whole lifecycle of the thread.
If you don't have control over how the new thread was created (e.g. in the new thread isn't newly created, or if the thread life cycle is managed by a #GThreadPool), it is always suggested to wrap the logic that needs to use the new #GMainContext inside a g_main_context_push_thread_default() / g_main_context_pop_thread_default() pair, otherwise threads that are re-used will end up never explicitly releasing the #GMainContext reference they hold.
In some cases you may want to schedule a single operation in a non-default context, or temporarily use a non-default context in the main thread. In that case, you can wrap the call to the asynchronous operation inside a g_main_context_push_thread_default() / g_main_context_pop_thread_default() pair, but it is up to you to ensure that no other asynchronous operations accidentally get started while the non-default context is active.
Beware that libraries that predate this function may not correctly handle being used from a thread with a thread-default context. Eg, see g_file_supports_thread_contexts().
Determines information necessary to poll this main loop. You should
be careful to pass the resulting fds array and its length n_fds
as is when calling g_main_context_check(), as this function relies
on assumptions made when the array is filled.
You must have successfully acquired the context with g_main_context_acquire() before you may call this function.
maximum priority source to check
Increases the reference count on a #GMainContext object by one.
Releases ownership of a context previously acquired by this thread with g_main_context_acquire(). If the context was acquired multiple times, the ownership will be released only when g_main_context_release() is called as many times as it was acquired.
Decreases the reference count on a #GMainContext object by one. If the result is zero, free the context and free all associated memory.
Tries to become the owner of the specified context,
as with g_main_context_acquire(). But if another thread
is the owner, atomically drop mutex and wait on cond until
that owner releases ownership or until cond is signaled, then
try again (once) to become the owner.
If context is currently blocking in g_main_context_iteration()
waiting for a source to become ready, cause it to stop blocking
and return. Otherwise, cause the next invocation of
g_main_context_iteration() to return without blocking.
This API is useful for low-level control over #GMainContext; for example, integrating it with main loop implementations such as #GMainLoop.
Another related use for this function is when implementing a main loop with a termination condition, computed from multiple threads:
#define NUM_TASKS 10
static gint tasks_remaining = NUM_TASKS; // (atomic)
...
while (g_atomic_int_get (&tasks_remaining) != 0)
g_main_context_iteration (NULL, TRUE);
Then in a thread:
perform_work();
if (g_atomic_int_dec_and_test (&tasks_remaining))
g_main_context_wakeup (NULL);
Returns the global default main context. This is the main context used for main loop functions when a main loop is not explicitly specified, and corresponds to the "main" main loop. See also g_main_context_get_thread_default().
Gets the thread-default #GMainContext for this thread. Asynchronous operations that want to be able to be run in contexts other than the default one should call this method or g_main_context_ref_thread_default() to get a #GMainContext to add their #GSources to. (Note that even in single-threaded programs applications may sometimes want to temporarily push a non-default context, so it is not safe to assume that this will always return %NULL if you are running in the default thread.)
If you need to hold a reference on the context, use g_main_context_ref_thread_default() instead.
Creates a new #GMainContext structure.
Creates a new #GMainContext structure.
a bitwise-OR combination of #GMainContextFlags flags that can only be set at creation time.
Gets the thread-default #GMainContext for this thread, as with g_main_context_get_thread_default(), but also adds a reference to it with g_main_context_ref(). In addition, unlike g_main_context_get_thread_default(), if the thread-default context is the global default context, this will return that #GMainContext (with a ref added to it) rather than returning %NULL.
The
GMainContextstruct is an opaque data type representing a set of sources to be handled in a main loop.