SIGSYS

From Wikipedia, the free encyclopedia

SIGSYS
Description Bad argument to routine (SVID)
Default action Abnormal termination of the process
SA_SIGINFO macros
None

On POSIX-compliant platforms, SIGSYS is the signal thrown by computer programs when a bad argument is passed to a system call. The symbolic constant for SIGSYS is 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. SYS refers to a system call.

[edit] Usage

Theoretically, in POSIX SIGSYS may be sent when a process supplies an incorrect argument to a system call. In practice, conforming implementations return ENOSYS if a code number does not correspond to a system call, or another error if a later argument is invalid (e.g. EBADF if a file descriptor does not exist). POSIX.1 has this to say about SIGSYS:

There is very little that a conforming POSIX.1 application can do by catching, ignoring or masking ... SIGSYS. ...
One portable use that does exist ... is that a command interpreter can recognize them as the cause of a process's termination.

[edit] See also


v • d • e
Computing signals
POSIX
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)
non-POSIX
Languages