SIGALRM

Template:Infobox Computing signal On POSIX-compliant platforms, SIGALRM is the signal thrown by computer programs when a time limit has elapsed. The symbolic constant for SIGALRM is defined in the signal.h header file. Symbolic signal names are used because signal numbers can vary across platforms.

Etymology

SIGs is a common prefix for signal names. ALRM stands for alarm.

Usage

Computer programs often use SIGALRM to make a long-running action time out, or to provide a way of performing an action at regular intervals.

SIGALRM is generally raised a whole number of seconds after an alarm system call is made. It is sometimes used to implement the sleep function; consequently, programs cannot reliably use alarm to "wake up" from a delay caused by sleep [1].