SIGSYS

Infobox Computing signal
description = Bad argument to routine (SVID)
action = Abnormal termination of the processOn 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.

Etymology

"SIG" is a common prefix for signal names. "SYS" refers to a system call.

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.

ee also

* [http://www.opengroup.org/austin/mailarchives/ag/msg00178.html Discussion of the utility of SIGSYS]