system

Purpose

     Runs a shell command.

Library

     Standard C Library (libc.a)

Syntax

     #include <stdio.h>

     int system (string)
     char *string;

Description

     The system subroutine passes  the string parameter to the
     sh  command as  input.  Then  sh interprets  string as  a
     command and runs it.

     The  system subroutine  invokes the  fork system  call to
     create  a child  process that  in turn  uses exec  to run
     /bin/sh, which interprets the  shell command contained in
     the string  parameter.  The  current process  waits until
     the shell has completed, then  returns the exit status of
     the shell.

     Note:  The system subroutine  runs only sh shell commands
     (also  called Bourne  shell commands).   The results  are
     unpredictable if the  string parameter is not  a valid sh
     shell command.

Return Value

     Upon successful completion, the system subroutine returns
     the exit status of the shell.  See "wait" for an explana-
     tion of the exit status.

     If the fork fails, then system returns a value of -1.  If
     the exec  fails, then  it returns  127.  It  either case,
     errno is set to indicate the error.

File

     /bin/sh

Related Information

     In  this book:   "exec:   execl,  execv, execle,  execve,
     execlp, execvp,"  "exit, _exit,"  "fork," and "wait."

     The  sh   command  in   AIX  Operating   System  Commands
     Reference.