kolibrios/programs/develop/libraries/newlib/stdlib/system.c
Sergey Semyonov (Serge) 2336060a0c newlib: update
git-svn-id: svn://kolibrios.org@1906 a494cfbc-eb01-0410-851d-a64ba20cac60
2011-03-11 18:52:24 +00:00

86 lines
1.8 KiB
C

/*
FUNCTION
<<system>>---execute command string
INDEX
system
INDEX
_system_r
ANSI_SYNOPSIS
#include <stdlib.h>
int system(char *<[s]>);
int _system_r(void *<[reent]>, char *<[s]>);
TRAD_SYNOPSIS
#include <stdlib.h>
int system(<[s]>)
char *<[s]>;
int _system_r(<[reent]>, <[s]>)
char *<[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
<<0>> if it is not.
With a command argument, the result of <<system>> is the exit status
returned by <</bin/sh>>.
PORTABILITY
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>>.
*/
#include <_ansi.h>
#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <_syslist.h>
#include <reent.h>
int
_DEFUN(_system_r, (ptr, s),
struct _reent *ptr _AND
_CONST char *s)
{
if (s == NULL)
return 0;
errno = ENOSYS;
return -1;
}
#ifndef _REENT_ONLY
int
_DEFUN(system, (s),
_CONST char *s)
{
return _system_r (_REENT, s);
}
#endif