All functions not in the this table are considered to be unsafe with respect to signals. In the presence of signals, all functions defined by IEEE Std 1003.1-2001 behave as defined when called from or interrupted by a signal-catching function, with a single exception: when a signal interrupts an unsafe function and the signal-catching function calls an unsafe function, the behavior is undefined.
Note that while
raise() is on the list of asynchronous-safe functions, it is specifically covered by SIG33-C. Do not recursively invoke the raise() function.
Signal handlers should be as concise as possible, ideally unconditionally setting a flag and returning. They may also call the