gimpsignal Portable signal handling. Portable signal handling. signal(2), signal(5 or 7), sigaction(2). A prototype for signal handler functions. Note that each function which takes or returns a variable of this type also accepts or may return special values defined by your system's signal.h header file (like @SIG_DFL or @SIG_IGN). @signum: The number of the signal. Useful if different signals are handled by a single handler. @signum: @handler: @flags: @Returns: