86 lines
1.8 KiB
C
86 lines
1.8 KiB
C
/*
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FUNCTION
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<<system>>---execute command string
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INDEX
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system
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INDEX
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_system_r
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ANSI_SYNOPSIS
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#include <stdlib.h>
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int system(char *<[s]>);
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int _system_r(void *<[reent]>, char *<[s]>);
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TRAD_SYNOPSIS
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#include <stdlib.h>
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int system(<[s]>)
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char *<[s]>;
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int _system_r(<[reent]>, <[s]>)
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char *<[reent]>;
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char *<[s]>;
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DESCRIPTION
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Use <<system>> to pass a command string <<*<[s]>>> to <</bin/sh>> on
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your system, and wait for it to finish executing.
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Use ``<<system(NULL)>>'' to test whether your system has <</bin/sh>>
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available.
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The alternate function <<_system_r>> is a reentrant version. The
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extra argument <[reent]> is a pointer to a reentrancy structure.
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RETURNS
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<<system(NULL)>> returns a non-zero value if <</bin/sh>> is available, and
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<<0>> if it is not.
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With a command argument, the result of <<system>> is the exit status
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returned by <</bin/sh>>.
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PORTABILITY
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ANSI C requires <<system>>, but leaves the nature and effects of a
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command processor undefined. ANSI C does, however, specify that
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<<system(NULL)>> return zero or nonzero to report on the existence of
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a command processor.
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POSIX.2 requires <<system>>, and requires that it invoke a <<sh>>.
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Where <<sh>> is found is left unspecified.
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Supporting OS subroutines required: <<_exit>>, <<_execve>>, <<_fork_r>>,
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<<_wait_r>>.
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*/
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#include <_ansi.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <_syslist.h>
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#include <reent.h>
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int
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_DEFUN(_system_r, (ptr, s),
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struct _reent *ptr _AND
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_CONST char *s)
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{
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if (s == NULL)
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return 0;
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errno = ENOSYS;
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return -1;
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}
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#ifndef _REENT_ONLY
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int
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_DEFUN(system, (s),
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_CONST char *s)
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{
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return _system_r (_REENT, s);
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}
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#endif
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