Blocking a signal means telling the operating system to hold it and
deliver it later. Generally, a program does not block signals
indefinitely—it might as well ignore them by setting their actions to
SIG_IGN. But it is useful to block signals briefly, to prevent
them from interrupting sensitive operations. For instance:
sigprocmaskfunction to block signals while you modify global variables that are also modified by the handlers for these signals.
sigactioncall to block certain signals while a particular signal handler runs. This way, the signal handler can run without being interrupted itself by signals.
|• Why Block:||The purpose of blocking signals.|
|• Signal Sets:||How to specify which signals to block.|
|• Process Signal Mask:||Blocking delivery of signals to your process during normal execution.|
|• Testing for Delivery:||Blocking to Test for Delivery of a Signal.|
|• Blocking for Handler:||Blocking additional signals while a handler is being run.|
|• Checking for Pending Signals:||Checking for Pending Signals|
|• Remembering a Signal:||How you can get almost the same effect as blocking a signal, by handling it and setting a flag to be tested later.|