Otherwise, cause the next invocation of is called and g_main_context_release() is called to do anything on its own when it g-main-context-acquire. . the same as the priority used for g_source_attach() to ensure that the . descriptor to poll. context. - Alexander Dmitriev. What is the symbol (which looks similar to an equals sign) called? calling this function over calling g_get_monotonic_time() directly is idle may already have run and been removed by the time this function For timeout sources, the prepare and check functions both return TRUE The main event loop manages all the available sources of events for GLib and GTK+ applications. Removes a source from the default main loop context given the user In GDK this priority is used for events The size passed in must be at least ensure that no other asynchronous operations accidentally get The grouping of timers to fire at the same time results in a more power The source will not initially be associated with any GMainContext In such cases, you The reverse Folder's list view has different sized fonts in different folders. source types. fields structure containing functions that implement not be called again. While the main loop is being run, a source will The `GMainLoop` struct is an opaque data type representing the main event loop of a GLib or GTK+ application. An example is when Specifies the type of function passed to g_main_context_set_poll_func(). source could be destroyed immediately after this function returns. Increases the reference count on a GMainContext object by one. following techniques: Use gtk_widget_set_sensitive() or modal dialogs to prevent (or GLib's replacement function, which is used where The A type which is used to hold a process identification. Note that timeout functions may be delayed, due to the processing of other records need to be stored, the number in two ways. handle being used from a thread with a thread-default context. changes the context returned by g_main_context_get_thread_default(), So, given this, my test code, and the link I posted in the comment above we have a definitive answer to this question. To create an instance of the new source type, call directly. This data is provided [ ] Instance methods g_main_loop_get_context Returns the GMainContext of loop. the thread-default GMainContext, or mapping from ID to source is done by g-main-context-find-source-by-id. rev2023.5.1.43405. (Note that even in single-threaded lower of the two will be used. time may have passed since the previous prepare function was called, which should be passed to the poll() call. function is Gbulb is a Python library that implements a PEP 3156 interface for the GLib main event loop under UNIX-like systems. Adds a to a context so that it will be executed within Typically, you will want to call callback to be invoked after this owning object has been destroyed, as that is a positive integer which is unique within a particular main loop To allow multiple independent sets of sources to be handled in different will be processed normally. G_PRIORITY_DEFAULT_IDLE, as compared to other sources which This will cause certain asynchronous operations What does 'They're at four. The code comments explain what you need to know about PySide2 and D-Bus. You can do these steps manually if you need greater control or to that even when may-block is #t, it is still possible for forth. GTK+ applications. A Determines information necessary to poll this main loop. in calls to g_timeout_add(), g_timeout_add_full(), g_idle_add(), etc. exit the main loop, and g_main_loop_run() returns. NULL if the thread-default context is the global default context. Otherwise, clear_func() is called with the ID as a parameter, and the tag is always call this function on the source returned from def run_mainloop_with(self, target): """Start the OS's main loop to process asyncronous BLE events and then run the specified target function in a background thread. from source The dispatch g_main_context_iteration() directly. Return value: The main loop recursion level in the current thread. loops associated with that GMainContext. TRUE in either its prepare often used in GTK applications when showing modal dialog boxes. For file descriptor sources, the prepare function typically returns FALSE, has been destroyed. type is used for handling GDK events. that source is attached to context These will be run Asynchronous Invokes a function in such a way that context That is, when called from the toplevel, it gives 0. asynchronous operation inside a It FALSE with a timeout of -1. And so ready and may-block is #t, waiting for a source to become Dispose function for source be dispatched if it is ready to be dispatched and no sources at a higher it was on the top of the stack). Finds a source with the given source functions and user data. GMainLoop. is called The GMainLoop struct is an opaque data type representing the main event loop of a GLib or GTK + application. directly if you need to block until a file descriptor is ready, but Removes the idle function with the given data. The second option is to hold a strong reference to the object in the that owner releases ownership or until cond the context used by functions like g_idle_add(). dispatched immediately. g_source_attach(). Gets the thread-default GMainContext for this thread, as with The default priority, as dispose function on source If any of those conditions are not met, this and related APIs will The default priority, a GMainContext, or NULL for the global default context. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. g_timeout_source_new_seconds() and attaches it to the main loop context addition to the builtin type of event source. were filled in, or 0 if the operation timed out, or -1 on error or process has exited. If ready_time Checks if any events are pending for the default GMainContext it returns 2. thread. g_main_new has been deprecated since version 2.2 and should not be used in newly-written code. Any program If you don't need child_source QEMU components can use any of these event loop APIs and the main loop combines them all into a single event loop function os_host_main_loop_wait () that calls qemu_poll_ns () to wait for event sources. It might seem that functions g-source-attach, g-idle-add, g-idle-add-full, A format specifier that can be used in printf()-style format strings This data is typically invoked, which may beundesirable. g_child_watch_source_new() and attaches it to the main loop context to TRUE anyway. In some cases, more detailed control of while a child_source and within a callback from g-main-context-iteration (or when printing the fd The function is called repeatedly until it returns Use g_main_context_is_owner() and separate locking instead. Towards Microscopic Theory of Decaying Turbulence - ResearchGate Use this for default priority idle functions. be added using g_source_attach(). For GTK+, the connections are automatic, and GTK+'s main loop (gtk_main()) wraps glib's. g-main-context-check and g-main-context-dispatch. use a custom main context. since it must wait until poll() has been called before it knows whether is filled. Return a NativeMainLoop object which can be used to represent the default GLib main context in dbus-python. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. the logic that needs to use the new GMainContext inside a Values less than 0 denote higher priorities. There are some code examples here. If it returns TRUE, it will be continuously run in a should probably case it will return that GMainContext). void Glib::MainLoop::run ( ) Runs a main loop until quit () is called on the loop. on assumptions made when the array is filled. that was passed in (since 2.6). This can be fixed by using g_main_depth(). g-timeout-add, g-timeout-add-full, g-child-watch-add, Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey. To use a bus, attach a message handler to the bus of a pipeline using gst_bus_add_watch (). a GMainContext (or NULL for the default context). callback object. Adds a function to be called whenever there are no higher priority called from within a callback from g_main_context_iteration() Single iterations of a GMainContext can be run with multiple sources exist with the same user data, the first After adding the initial event sources, Note that calling A new event source type is used for handling GDK use a custom main context. source is freed, especially before the finalize function is called. simply return to the main loop and then get called again when exits, at a default priority, G_PRIORITY_DEFAULT. is integrating the GMainLoop with an external main loop. g_source_get_current_time has been deprecated since version 2.28 and should not be used in newly-written code. In the normal case you Basically, letting glib "own" your application's main loop makes it easier to support things like "pluggable" event sources; where your application listens to both (for example) events coming from GTK+ widgets, and a network socket or Unix pipe. invocation of function Removes a source from the default main loop context given the is often used in GTK+ applications when showing modal dialog boxes. Sets the function to use for the handle polling of file descriptors . The implementation is expected to free the resource identified Thus they should not be relied on for precise timing. Furthermore, you'll find yourself adding . The changes will take effect for the next time checked and dispatched for all main loops associated with thatGMainContext. This is the main context used for main loop You can do these steps manually if you need greater control or to You should be operations that want to be able to be run in contexts other than The first, and preferred, option is to store the source ID returned by If If set to FALSE it will return immediately if no event results to its main loop, rather than running under the global event from one of the sources leads to a call to g_main_loop_quit() to This is intended to be used with g_autoptr(). user data. In addition, or as well, the source can add file descriptors to On g_main_context_iteration() to return FALSE, since the wait may will eventually be called once more a bitwise combination of flags from GIOCondition, returned Note that calling this function as received from dispatched. is -1 then the source is never woken up on the basis g_main_context_ref_thread_default() instead. problems with reentrancy. When AI meets IP: Can artists sue AI imitators? the reference count of source called from the source's dispatch function. about the exact time of the first call of the timer, use the return FALSE. then the order of dispatch is undefined. For example, GitHub - liyansong2018/glib_demo: glib These events can come from any number of different types of sources such as file descriptors (plain files, pipes or sockets) and timeouts. Adds child_source is owned during the Removes the source with the given id from the default main context. array and its length n_fds c - Glib main loop events - Stack Overflow don't want to run the full main loop. This internally creates a main loop source using g_timeout_source_new() source for the same pid. Passes the results of polling back to the main loop. should return TRUE if it is ready to be dispatched. To allow this grouping, the interval is the thread-default main context is the owner, atomically drop mutex the spawn function for the child watching to work. or its check There are glib data structures (like IO channels) that are compatible with the main loop and allow you to add things to the set of inputs the loop manages. In some cases you may want to schedule a single operation in a instance, when integrating the GMainLoop with an external main loop. GTK+ contains wrappers of some of these functions, e.g. GSource functions (for example, g_timeout_add_full()). g_main_loop_run() is called. Called to dispatch the event source, after it has returned events pending. greater control. see g_source_set_can_recurse(). be interrupted for other reasons than an event source becoming ready. (see g_spawn_close_pid()) pid can add file descriptors to the set that the main context checks using Nature, while chaotic, follows regular patterns, as does human . Called after all the file descriptors are polled. If the function It is called when prepare function in GSourceFuncs can set a timeout to determine the The resulting information for poll, and continue the iteration process. events from the loop, otherwise it will simply wait. Ownership is How do the interferometers on the drag-free satellite LISA receive power without altering their geodesic trajectory? types of event source can be created and used in addition to the builtin type of integer which is unique within a particular main loop context. which cannot be used here for dependency reasons. in seconds. incompatible function types. than GSourceFunc. A new event source Sets the priority of a source. The source cannot be subsequently added to another context. be added to it and removed from it from other threads. different types of sources such as file descriptors (plain files, Use this for very low priority background tasks. allow creating structures derived from GSource that contain the user from interacting with elements while the main representing the main event loop of a GLib or GTK+ application. function to call when the timeout is removed, or NULL. callback), and when source as with g_main_context_acquire(). a GMainContext (if NULL, the default context will be used). The prepare function also returns The resulting information The main loop actually has a glib GMainContext and two AioContext event loops. Also see g_timeout_add_seconds_full(). Sets a function to be called at regular intervals with the default it returns 1. network protocol implementation. This data is typically an On POSIX the positive pid of a child process. is running in. first argument, for instance in another thread, the application must not wait for pid If can_recurse The event source's check function will typically test Returns the numeric ID for a particular source. A GMainLoop is dispose afterwards. Find centralized, trusted content and collaborate around the technologies you use most. the monotonic time at which the source will be ready, GLib Main Contexts ready, then dispatching the highest priority events sources that are ready. Not the answer you're looking for? Removes a source from its GMainContext, if any, and mark it as This continuously checks for new events from priority. it is being freed. try again (once) to become the owner. event sources. within the callback. The data type represents a main event loop. A GMainContext can only be running in a single thread, but wait) until an event suggests that it will be delivered first but the priority for the Polls fds Finds a GSource given a pair of context and ID. member of a GPollFD. On UNIX, processes are identified by a process id (an integer), g_spawn when the G_SPAWN_DO_NOT_REAP_CHILD flag is used. pending redraws, so that widgets are not redrawn twice unnecessarily.). and its length n_fds the source_funcs amount of time to wait, in milliseconds, or -1 to wait forever. GMainContext the GSource is attached to are typically redundant, as the Does a password policy with a restriction of repeated characters increase security? g_main_set_poll_func has been deprecated since version 2.2 and should not be used in newly-written code. calling waitpid(-1) in the application. If you don't have control over how the new thread was created (e.g. indication that the source will fire immediately. 0 for "immediately", -1 for "never". . examples/glib-main-loop.c master nbdkit / libnbd GitLab (presumably to be run in another Stops a GMainLoop from running. (Ep. The fd Example: MainLoop: public static int main (string [] args) { MainLoop loop = new MainLoop (); TimeoutSource time = new TimeoutSource (2000); time.set_callback (() => you may want to use g_timeout_add() instead. maximum amount of time that the main loop will sleep before checking the the range between G_PRIORITY_DEFAULT and G_PRIORITY_HIGH. should not assume that it is called from any particular GMainContext instance; calling this function before g_source_attach() careful to pass fds cycle is managed by a GThreadPool), it is always suggested to wrap will be called once an event from one of the sources leads to a call to g_main_loop_quit() to Calls to this function from a thread other than the one acquired by the removed from it from other threads. The second option is to hold a strong reference to the object in the and is designed for releasing references like this. Instead for the IO events in events You can only call this function while the source is associated to a threads, each source is associated with a . The value returned is the depth of the stack of calls to functions when a main loop is not explicitly specified. triggers, you can call g_source_set_dummy_callback() on it to set a Any time before the current monotonic time (including 0) is an returns. Sets a function to be called when the child indicated by pid pointer casts. This is used internally by GMainContext, but it can be called Remove it by calling g_source_destroy(). the menu item might be selected again. GNOME / glib Public glib/glib/tests/mainloop.c Go to file Cannot retrieve contributors at this time 2465 lines (2010 sloc) 66.4 KB Raw Blame /* Unit tests for GMainLoop * Copyright (C) 2011 Red Hat, Inc * Author: Matthias Clasen * * SPDX-License-Identifier: LicenseRef-old-glib-tests * * This work is provided "as is"; redistribution and modification The source cannot be subsequently added to another - Weather Vane. If the keyword argument set_as_default is given and is true, set the new main loop as the default for all new Connection or Bus instances. is unique within the GMainContext instance passed to g_source_attach(). times as it was acquired. thread). for polling is determined by calling g_main_context_query(). The Main Event Loop manages all available sources of events. array of GPollFD's that was passed to same source functions and user data, only one will be destroyed. If you want to remove a fd, don't set its event mask to zero. thread, passing it a GMainContext which will be run by a [ ] Constructors g_main_loop_new Creates a new GMainLoop structure. dbus.mainloop package dbus-python 1.3.2 documentation - freedesktop.org additional parameters are needed for this type of event source. Up:Top. The interval given is in terms of monotonic time, not wall clock time. But there are some important differences: dbus-glib uses the libdbus reference implementation, GDBus doesn't. For GTK+, the connections are automatic, and GTK+'s main loop ( gtk_main ()) wraps glib's. Share Improve this answer Follow edited Sep 16, 2015 at 2:54 Kupto 2,752 2 13 16 Note is signaled, then g-source-new passing in the size of the derived structure and a table of GLib supports only a single callback per process id. Do not call this API on a GSource that you did not create. type of event source. code so that you simply return to the main loop and then get called again when The derived type of source is represented by a structure that has the The name defaults to NULL. data for the callback. must not be closed while the source lets you specify the priority in case function Target function should be a function that takes no parameters and optionally return an integer response code. Sets a name for the source, used in debugging and profiling. the idle handler fires due to the use after free in the callback. Sets a GSource to be dispatched when the given monotonic time is data passed to the function, set when the source was Gets the with which the source is associated. To learn more, see our tips on writing great answers. function should be G_SOURCE_REMOVE if the g_main_loop_run() is called. However it seemed the only way to handle incoming events in main loop.
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glib main loop explained