SIGALRM
From Wikipedia, the free encyclopedia
| Description: | Alarm clock |
|---|---|
| Default action: | Abnormal termination of the process |
| SA_SIGINFO macros | |
| None | |
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.
[edit] Etymology
SIG is a common prefix for signal names. ALRM stands for alarm.
[edit] 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.
| POSIX Signals |
| SIGABRT | SIGALRM | SIGFPE | SIGHUP | SIGILL | SIGINT | SIGKILL | SIGPIPE | SIGQUIT | SIGSEGV | SIGTERM | SIGUSR1 | SIGUSR2 | SIGCHLD | SIGCONT | SIGSTOP | SIGTSTP | SIGTTIN | SIGTTOU | SIGBUS | SIGPOLL | SIGPROF | SIGSYS | SIGTRAP | SIGURG | SIGVTALRM | SIGXCPU | SIGXFSZ | Realtime Signals are user definable—SIGRTMIN+n through SIGRTMAX. |
| Common non-POSIX signals and synonyms |
| SIGIOT | SIGEMT | SIGSTKFLT | SIGIO | SIGCLD | SIGINFO | SIGPWR (SIGINFO) | SIGLOST | SIGWINCH | SIGUNUSED |
