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.