system

来自「Calc Software Package for Number Calc」· 代码 · 共 71 行

NAME
    system - issue a shell command

SYNOPSIS
    system(cmd)

TYPES
    cmd		str

    return	int

DESCRIPTION
    This function excutes the shell command found in the srtring, cmd.
    The return value is system dependent.  On POSIX P1003.1 compliant
    systems the return value is defined by the waitpid system call.
    Typically a shell command that returns with a 0 exit status will
    cause this function to return a 0 value.  On some systems, a shell
    command that returns with an exit status of e will cause this
    function to return e*256.  Core dumps, termination due to signals
    and other waitpid values will change the return value.

    On POSIX P1003.1 compliant systems, if cmd is empty then this function
    will determine if the shell is executable.	If the shell is executable,
    0 is returned otherwise non-zero is returned.

EXAMPLE
    ; system("")
	    0
    ; system("true")
	    0
    ; system("exit 2")
	    512
    ; system("date")
    Sun Jul  9 03:21:48 PDT 1995
	    0

LIMITS
    none

LINK LIBRARY
    none

SEE ALSO
    cmdbuf, argv

## Copyright (C) 1999-2006  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
##
## @(#) $Revision: 29.4 $
## @(#) $Id: system,v 29.4 2006/06/25 22:16:55 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/system,v $
##
## Under source code control:	1995/07/09 03:48:57
## File existed as early as:	1995
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/