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
is 0. All members filled into the
GSignalQuery structure should
be considered constant and have to be left untouched.
The signal id of the signal to query information for.
A user provided structure that is filled in with constant values upon success.
The argument will be set by the function. The data is owned by the function.