Blocking Signals (The GNU C Library) (original) (raw)

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24.7 Blocking Signals

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 toSIG_IGN. But it is useful to block signals briefly, to prevent them from interrupting sensitive operations. For instance:

• You can use the sigprocmask function to block signals while you modify global variables that are also modified by the handlers for these signals.
• You can set sa_mask in your sigaction call to block certain signals while a particular signal handler runs. This way, the signal handler can run without being interrupted itself by signals.
• Why Blocking Signals is Useful
• Signal Sets
• Process Signal Mask
• Blocking to Test for Delivery of a Signal
• Blocking Signals for a Handler
• Checking for Pending Signals
• Remembering a Signal to Act On Later