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
avail-able.
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 0
if 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
561
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.
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