A predefined GSignalAccumulator for signals intended to be used as a hook for application code to provide a particular value. Usually only one such value is desired and multiple handlers for the same signal don't make much sense (except for the case of the default handler defined in the class structure, in which case you will usually want the signal connection to override the class handler). This accumulator will use the return value from the first signal handler that is run as the return value for the signal and not run any further handlers (ie: the first handler "wins"). Since 2.28
A predefined GSignalAccumulator for signals that return a boolean values. The behavior that this accumulator gives is that a return of TRUE stops the signal emission: no further callbacks will be invoked, while a return of FALSE allows the emission to continue. The idea here is that a TRUE return indicates that the callback handled the signal, and no further handling is needed. Since 2.4 [10] Although signals can deal with any kind of instantiatable type, i'm referring to those types as "object types" in the following, simply because that is the context most users will encounter signals in.
Adds an emission hook for a signal, which will get called for any emission of that signal, independent of the instance. This is possible only for signals which don't have G_SIGNAL_NO_HOOKS flag set.
Calls the original class closure of a signal. This function should only be called from an overridden class closure; see g_signal_override_class_closure() and g_signal_override_class_handler().
Connects a closure to a signal for a particular object.
Connects a closure to a signal for a particular object.
Connects a GCallback function to a signal for a particular object. Similar to g_signal_connect(), but allows to provide a GClosureNotify for the data which will be called when the signal handler is disconnected and no longer used. Specify connect_flags if you need ..._after() or ..._swapped() variants of this function.
This is similar to g_signal_connect_data(), but uses a closure which ensures that the gobject stays alive during the call to c_handler by temporarily adding a reference count to gobject. When the gobject is destroyed the signal handler will be automatically
Emits a signal. Note that g_signal_emit_valist() resets the return value to the default if no handlers are connected, in contrast to g_signal_emitv().
Emits a signal. Note that g_signal_emitv() doesn't change return_value if no handlers are connected, in contrast to g_signal_emit() and g_signal_emit_valist().
Returns the invocation hint of the innermost signal emission of instance.
Blocks a handler of an instance so it will not be called during any signal emissions unless it is unblocked again. Thus "blocking" a signal handler means to temporarily deactive it, a signal handler has to be unblocked exactly the same amount of times it has been blocked before to become active again. The handler_id has to be a valid signal handler id, connected to a signal of instance.
Disconnects a handler from an instance so it will not be called during any future or currently ongoing emissions of the signal it has been connected to. The handler_id becomes invalid and may be reused. The handler_id has to be a valid signal handler id, connected to a signal of instance.
Finds the first signal handler that matches certain selection criteria. The criteria mask is passed as an OR-ed combination of GSignalMatchType flags, and the criteria values are passed as arguments. The match mask has to be non-0 for successful matches. If no handler was found, 0 is returned.
Returns whether handler_id is the id of a handler connected to instance.
Undoes the effect of a previous g_signal_handler_block() call. A blocked handler is skipped during signal emissions and will not be invoked, unblocking it (for exactly the amount of times it has been blocked before) reverts its "blocked" state, so the handler will be recognized by the signal system and is called upon future or currently ongoing signal emissions (since the order in which handlers are called during signal emissions is deterministic, whether the unblocked handler in question is called as part of a currently ongoing emission depends on how far that emission has proceeded yet). The handler_id has to be a valid id of a signal handler that is connected to a signal of instance and is currently blocked.
Blocks all handlers on an instance that match a certain selection criteria. The criteria mask is passed as an OR-ed combination of GSignalMatchType flags, and the criteria values are passed as arguments. Passing at least one of the G_SIGNAL_MATCH_CLOSURE, G_SIGNAL_MATCH_FUNC or G_SIGNAL_MATCH_DATA match flags is required for successful matches. If no handlers were found, 0 is returned, the number of blocked handlers otherwise.
Disconnects all handlers on an instance that match a certain selection criteria. The criteria mask is passed as an OR-ed combination of GSignalMatchType flags, and the criteria values are passed as arguments. Passing at least one of the G_SIGNAL_MATCH_CLOSURE, G_SIGNAL_MATCH_FUNC or G_SIGNAL_MATCH_DATA match flags is required for successful matches. If no handlers were found, 0 is returned, the number of disconnected handlers otherwise.
Unblocks all handlers on an instance that match a certain selection criteria. The criteria mask is passed as an OR-ed combination of GSignalMatchType flags, and the criteria values are passed as arguments. Passing at least one of the G_SIGNAL_MATCH_CLOSURE, G_SIGNAL_MATCH_FUNC or G_SIGNAL_MATCH_DATA match flags is required for successful matches. If no handlers were found, 0 is returned, the number of unblocked handlers otherwise. The match criteria should not apply to any handlers that are not currently blocked.
Returns whether there are any handlers connected to instance for the given signal id and detail. One example of when you might use this is when the arguments to the signal are difficult to compute. A class implementor may opt to not emit the signal if no one is attached anyway, thus saving the cost of building the arguments.
Lists the signals by id that a certain instance or interface type created. Further information about the signals can be acquired through g_signal_query().
Given the name of the signal and the type of object it connects to, gets the signal's identifying integer. Emitting the signal by number is somewhat faster than using the name each time. Also tries the ancestors of the given type. See g_signal_new() for details on allowed signal names.
Given the signal's identifier, finds its name. Two different signals may have the same name, if they have differing types.
Creates a new signal. (This is usually done in the class initializer.) See g_signal_new() for details on allowed signal names. If c_marshaller is NULL, g_cclosure_marshal_generic() will be used as the marshaller for this signal.
Creates a new signal. (This is usually done in the class initializer.) See g_signal_new() for details on allowed signal names. If c_marshaller is NULL g_cclosure_marshal_generic will be used as the marshaller for this signal.
Overrides the class closure (i.e. the default handler) for the given signal for emissions on instances of instance_type. instance_type must be derived from the type to which the signal belongs. See g_signal_chain_from_overridden() and g_signal_chain_from_overridden_handler() for how to chain up to the parent class closure from inside the overridden one.
Overrides the class closure (i.e. the default handler) for the given signal for emissions on instances of instance_type with callback class_handler. instance_type must be derived from the type to which the signal belongs. See g_signal_chain_from_overridden() and g_signal_chain_from_overridden_handler() for how to chain up to the parent class closure from inside the overridden one. Since 2.18
Internal function to parse a signal name into its signal_id and detail quark.
Queries the signal system for in-depth information about a specific signal. This function will fill in a user-provided structure to hold signal-specific information. If an invalid signal id is passed in, the signal_id member of the GSignalQuery is 0. All members filled into the GSignalQuery structure should be considered constant and have to be left untouched.
Deletes an emission hook.
Stops a signal's current emission. This will prevent the default method from running, if the signal was G_SIGNAL_RUN_LAST and you connected normally (i.e. without the "after" flag). Prints a warning if used on a signal which isn't being emitted.
Stops a signal's current emission. This is just like g_signal_stop_emission() except it will look up the signal id for you.
Creates a new closure which invokes the function found at the offset struct_offset in the class structure of the interface or classed type identified by itype.
The basic concept of the signal system is that of the emission of a signal. Signals are introduced per-type and are identified through strings. Signals introduced for a parent type are available in derived types as well, so basically they are a per-type facility that is inherited. A signal emission mainly involves invocation of a certain set of callbacks in precisely defined manner. There are two main categories of such callbacks, per-object [10] ones and user provided ones. The per-object callbacks are most often referred to as "object method handler" or "default (signal) handler", while user provided callbacks are usually just called "signal handler". The object method handler is provided at signal creation time (this most frequently happens at the end of an object class' creation), while user provided handlers are frequently connected and disconnected to/from a certain signal on certain object instances.
A signal emission consists of five stages, unless prematurely stopped:
1 - Invocation of the object method handler for G_SIGNAL_RUN_FIRST signals
2 - Invocation of normal user-provided signal handlers (after flag FALSE)
3 - Invocation of the object method handler for G_SIGNAL_RUN_LAST signals
4 - Invocation of user provided signal handlers, connected with an after flag of TRUE
5 - Invocation of the object method handler for G_SIGNAL_RUN_CLEANUP signals
The user-provided signal handlers are called in the order they were connected in. All handlers may prematurely stop a signal emission, and any number of handlers may be connected, disconnected, blocked or unblocked during a signal emission. There are certain criteria for skipping user handlers in stages 2 and 4 of a signal emission. First, user handlers may be blocked, blocked handlers are omitted during callback invocation, to return from the "blocked" state, a handler has to get unblocked exactly the same amount of times it has been blocked before. Second, upon emission of a G_SIGNAL_DETAILED signal, an additional "detail" argument passed in to g_signal_emit() has to match the detail argument of the signal handler currently subject to invocation. Specification of no detail argument for signal handlers (omission of the detail part of the signal specification upon connection) serves as a wildcard and matches any detail argument passed in to emission.