system

 

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 Standard C Library Functions                           system(3C)
 
 
 


NAME
      system - issue a shell command
 


SYNOPSIS
      #include <stdlib.h>
 
      int system(const char *string);
 


DESCRIPTION
      The system() function causes string to be given to the shell
      as input, as if string had been typed as a command at a ter-
      minal. The invoker waits until the shell has completed, then
      returns the exit status of the shell in the format specified
      by waitpid(2).
 
      If string is a null pointer, system() checks  if  the  shell
      exists  and  is executable.  If the shell is available, sys-
      tem() returns a non-zero value; otherwise, it returns 0.  If
      the  application  is standard-conforming (see standards(5)),
      system() uses /usr/bin/ksh (see ksh(1)); otherwise  system()
      uses /usr/bin/sh (see sh(1)).
 
 RETURN VALUES
      The system() function forks to create a child  process  that
      in  turn  invokes  one  of the exec family of functions (see
      exec(2)) on the shell to execute string. If vfork(2) or  the
      exec  function  fails, system() returns -1 and sets errno to
      indicate the error.
 
 ERRORS
      The system() function fails if:
 
      EAGAIN
            The  system-imposed  limit  on  the  total  number  of
            processes  under  execution  by a single user would be
            exceeded.
 
      EINTR The system() function was interrupted by a signal.
 
      ENOMEM
            The new process requires more memory  than  is  avail-
            able.
 
 USAGE
      The system() function will fail to execute setuid() or  set-
      gid()  if  either  the  UID  or  GID  of  the  application's
      owner/group is less than 100. See useradd(1M) and setuid(2).
 
      The system() function is implemented using  vfork(2),  which
      is much less likely to fail due to resource constraints than
      fork(2).
 
 
 
 
 SunOS 5.8           Last change: 12 Oct 1999                    1
 
 
 
 
 
 
 Standard C Library Functions                           system(3C)
 
 
 


ATTRIBUTES
      See attributes(5) for descriptions of the  following  attri-
      butes:
 
      ____________________________________________________________
     |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
     |_____________________________|_____________________________|
     | MT-Level                    | Unsafe                      |
     |_____________________________|_____________________________|
 
 


SEE ALSO
      ksh(1), sh(1),  useradd(1M),  exec(2),  fork(2),  setuid(2),
      vfork(2), waitpid(2), attributes(5), standards(5)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 SunOS 5.8           Last change: 12 Oct 1999                    2
 
 
 

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