SIGVTALRM
From Wikipedia, the free encyclopedia
| 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.
| 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 |
