system[execute command string]

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system
[execute command string]

SYNOPSIS
#include<stdlib.h>
int system(char *s);

int _system_r(void *reent, char *s);

DESCRIPTION
Use system to pass a command string, *s, to /bin/sh on your system, and wait for it to finish executing. Use system(NULL) to test whether your system has /bin/sh available.

The alternate function, _system_r, is a reentrant version. The extra argument, reent,is a pointer to a reentrancy structure.

RETURNS
system(NULL)returns a non-zero value if /bin/sh is available, and 0if it is not. With a command argument, the result of system is the exit status returned by /bin/sh.

COMPLIANCE
ANSI C requires system, but leaves the nature and effects of a command processor undefined. ANSI C does, however, specify that system(NULL) return zero or nonzero to report on the existence of a command processor.

POSIX.2 requires system, and requires that it invoke a sh. Where sh is found is left unspecified.

Supporting OS subroutines required: _exit, _execve, _fork_r, _wait_r.