Emitted when the operation has been cancelled.
Can be used by implementations of cancellable operations. If the
operation is cancelled from another thread, the signal will be
emitted in the thread that cancelled the operation, not the
thread that is running the operation.
Note that disconnecting from this signal (or any signal) in a
multi-threaded program is prone to race conditions. For instance
it is possible that a signal handler may be invoked even
after a call to
g_signal_handler_disconnect() for that handler has already
returned.
There is also a problem when cancellation happen
right before connecting to the signal. If this happens the
signal will unexpectedly not be emitted, and checking before
connecting to the signal leaves a race condition where this is
still happening.
In order to make it safe and easy to connect handlers there
are two helper functions: g_cancellable_connect() and
g_cancellable_disconnect() which protect against problems
like this.
Note that the cancelled signal is emitted in the thread that
the user cancelled from, which may be the main thread. So, the
cancellable signal should not do something that can block.
Emitted when the operation has been cancelled. Can be used by implementations of cancellable operations. If the operation is cancelled from another thread, the signal will be emitted in the thread that cancelled the operation, not the thread that is running the operation. Note that disconnecting from this signal (or any signal) in a multi-threaded program is prone to race conditions. For instance it is possible that a signal handler may be invoked even after a call to g_signal_handler_disconnect() for that handler has already returned. There is also a problem when cancellation happen right before connecting to the signal. If this happens the signal will unexpectedly not be emitted, and checking before connecting to the signal leaves a race condition where this is still happening. In order to make it safe and easy to connect handlers there are two helper functions: g_cancellable_connect() and g_cancellable_disconnect() which protect against problems like this. Note that the cancelled signal is emitted in the thread that the user cancelled from, which may be the main thread. So, the cancellable signal should not do something that can block.