SIGVTALRM

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SIGVTALRM
Description Virtual alarm clock (4.2BSD)
Default action Abnormal termination of the process
SA_SIGINFO macros
None

On POSIX-compliant platforms, SIGVTALRM is the signal thrown by computer programs when a time limit has elapsed. In source code, SIGVTALRM is a symbolic constant defined in the header file signal.h. Symbolic signal names are used because signal numbers can vary across platforms.

[edit] Etymology

SIG is a common prefix for signal names. VTALRM is an abbreviation for virtual alarm.

[edit] Usage

SIGVTALRM is sent when a timer expires, like SIGPROF and the more popular SIGALRM. The distinction of SIGVTALRM is that its timer counts only time spent executing the process itself; SIGPROF measures time spent by the process and by the system executing on behalf of the process, while SIGALRM measures real time. It is suggested[citation needed] that SIGPROF be used with SIGVTALRM to profile the time spent by the process in user space and kernel space.

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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)
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