Optionalproperties: Partial<{}>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 GLib.MainContext.release is called as many times as GLib.MainContext.acquire.
You must be the owner of a context before you can call GLib.MainContext.prepare, GLib.MainContext.query, GLib.MainContext.check, GLib.MainContext.dispatch, GLib.MainContext.release.
Since 2.76 context can be NULL to use the global-default
main context.
true if this thread is now the owner of context, false otherwise
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 GLib.PollFD 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 GLib.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
GLib.MainContext.query, as this functions relies on assumptions
on how fds is filled.
You must have successfully acquired the context with GLib.MainContext.acquire before you may call this function.
Since 2.76 context can be NULL to use the global-default
main context.
the maximum numerical priority of sources to check
array of GLib.PollFDs that was passed to the last call to GLib.MainContext.query
true if some sources are ready to be dispatched, false otherwise
Dispatches all pending sources.
You must have successfully acquired the context with GLib.MainContext.acquire before you may call this function.
Since 2.76 context can be NULL to use the global-default
main context.
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 GLib.Source.new
Optionaluser_data: anythe user data from the callback
the source, if one was found, otherwise NULL
Finds a GLib.Source 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 GLib.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 GLib.Source.get_id
the source
Invokes a function in such a way that context is owned during the
invocation of function.
This function is the same as GLib.MainContext.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 GLib.DestroyNotify
for data.
The notify function 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
Optionalnotify: DestroyNotifya function to call when data is no longer in use
Determines whether this thread holds the (recursive) ownership of this GLib.MainContext.
This is useful to
know before waiting on another thread that may be
blocking to get ownership of context.
true if current thread is owner of context, false otherwise
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,
this function does not wait for sources to become ready, and only the highest
priority sources which are already ready (if any) will be dispatched.
Note that even when may_block is true, it is still possible for
GLib.MainContext.iteration to return false, since the wait may
be interrupted for other reasons than an event source becoming ready.
whether the call may block
true if events were dispatched, false otherwise
Checks if any sources have pending events for the given context.
true if events are pending, false otherwise
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 GLib.MainContext.query.
You must have successfully acquired the context with GLib.MainContext.acquire before you may call this function.
true if some source is ready to be dispatched prior to polling, false otherwise
Acquires context and sets it as the thread-default context for the
current thread. This will cause certain asynchronous operations
(such as most 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 main context in the main thread. Note that calling this function
changes the context returned by GLib.MainContext.get_thread_default,
not the one returned by GLib.MainContext.default, so it does not
affect the context used by functions like GLib.idle_add.
Normally you would call this function shortly after creating a new thread, passing it a GLib.MainContext which will be run by a GLib.MainLoop 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 GLib.MainContext.pop_thread_default, assuming you want the new GLib.MainContext 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 GLib.ThreadPool), it is always suggested to wrap the logic that needs to use the new GLib.MainContext inside a GLib.MainContext.push_thread_default / GLib.MainContext.pop_thread_default pair, otherwise threads that are re-used will end up never explicitly releasing the GLib.MainContext 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 GLib.MainContext.push_thread_default / GLib.MainContext.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. For example,
see g_file_supports_thread_contexts().
Push main_context as the new thread-default main context for the current
thread, using GLib.MainContext.push_thread_default, and return a
new GLib.MainContextPusher. Pop with g_main_context_pusher_free().
Using GLib.MainContext.pop_thread_default on main_context while a
GLib.MainContextPusher exists for it can lead to undefined behaviour.
Using two GLib.MainContextPushers in the same scope is not allowed, as it leads to an undefined pop order.
This is intended to be used with g_autoptr(). Note that g_autoptr()
is only available when using GCC or clang, so the following example
will only work with those compilers:
typedef struct
{
...
GMainContext *context;
...
} MyObject;
static void
my_object_do_stuff (MyObject *self)
{
g_autoptr(GMainContextPusher) pusher = g_main_context_pusher_new (self->context);
// Code with main context as the thread default here
if (cond)
// No need to pop
return;
// Optionally early pop
g_clear_pointer (&pusher, g_main_context_pusher_free);
// Code with main context no longer the thread default here
}
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 GLib.MainContext.check, as this function relies
on assumptions made when the array is filled.
You must have successfully acquired the context with GLib.MainContext.acquire before you may call this function.
maximum priority source to check
the number of records actually stored in fds, or, if more than n_fds records need to be stored, the number of records that need to be stored
Increases the reference count on a GLib.MainContext object by one.
the context that was passed in (since 2.6)
Releases ownership of a context previously acquired by this thread with GLib.MainContext.acquire.
If the context was acquired multiple times, the ownership will be released only when GLib.MainContext.release is called as many times as it was acquired.
You must have successfully acquired the context with GLib.MainContext.acquire before you may call this function.
Removes file descriptor from the set of file descriptors to be polled for a particular context.
a GLib.PollFD descriptor previously added with GLib.MainContext.add_poll
Decreases the reference count on a GLib.MainContext 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, and waits on cond if
another thread is the owner.
This is the same as GLib.MainContext.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.
true if this thread is now the owner of context, false otherwise
Wake up context if it’s currently blocking in
GLib.MainContext.iteration, causing it to stop blocking.
The context could be blocking waiting for a source to become ready.
Otherwise, if context is not currently blocking, this function causes the
next invocation of GLib.MainContext.iteration to return without
blocking.
This API is useful for low-level control over GLib.MainContext; for example, integrating it with main loop implementations such as GLib.MainLoop.
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);
StaticdefaultReturns 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 GLib.MainContext.get_thread_default.
Staticget_Gets the thread-default main context 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
GLib.MainContext.ref_thread_default to get a
GLib.MainContext to add their GLib.Sources 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 GLib.MainContext.ref_thread_default instead.
StaticnewStaticnew_Staticref_Gets a reference to the thread-default GLib.MainContext for this thread
This is the same as GLib.MainContext.get_thread_default, but it also
adds a reference to the returned main context with GLib.MainContext.ref.
In addition, unlike
GLib.MainContext.get_thread_default, if the thread-default context
is the global-default context, this will return that
GLib.MainContext (with a ref added to it) rather than returning
NULL.
The GLib.MainContext struct is an opaque data type representing a set of sources to be handled in a main loop.