system(3) - NetBSD Manual Pages

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SYSTEM(3)               NetBSD Library Functions Manual              SYSTEM(3)


NAME

     system -- pass a command to the shell


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <stdlib.h>

     int
     system(const char *string);


DESCRIPTION

     The system() function hands the argument string to the command inter-
     preter sh(1).  The calling process waits for the shell to finish execut-
     ing the command, ignoring SIGINT and SIGQUIT, and blocking SIGCHLD.

     If string is a NULL pointer, system() will return non-zero, if the com-
     mand interpreter is available, or zero if none is available.  Otherwise,
     system() returns the termination status of the shell in the format speci-
     fied by waitpid(2).


RETURN VALUES

     If a child process cannot be created, or the termination status of the
     shell cannot be obtained, system() returns -1 and sets errno to indicate
     the error.  If execution of the shell fails, system() returns the termi-
     nation status for a program that terminates with a call of exit(127).


SEE ALSO

     sh(1), execve(2), waitpid(2), popen(3), shquote(3)


STANDARDS

     The system() function conforms to ANSI X3.159-1989 (``ANSI C89'') and
     IEEE Std 1003.2-1992 (``POSIX.2'').


CAVEATS

     Never supply the system() function with a command containing any part of
     an unsanitized user-supplied string.  Shell meta-characters present will
     be honored by the sh(1) command interpreter.

NetBSD 5.1.2                    August 2, 2007                    NetBSD 5.1.2