EXEC(3)                        Library Routines                        EXEC(3)

NAME

       exec - load an executable file and launch as a new process

SYNOPSIS

       #include <unistd.h>

       int exec(const char *pathname, const char *cmdline);

DESCRIPTION

       This  call  is  provided  only for backward compatibility and should be
       avoided.  New programs should use the execve(2) family  of  calls,  the
       system(3) routine, or the EXECUTE shell call.

       exec  is  an  alternative method for launching a new process under GNO.
       It is a combination of the fork(2) and _execve(2) system calls, and  is
       in fact written in terms of them.  The difference between exec and _ex����
       ecve is that exec returns in all cases; it is  a  simplified  interface
       for those who don't need to affect process information before a new ex‐
       ecutable begins (such as process group IDs or I/O redirection  informa‐
       tion).

       The (somewhat simplified) algorithm for exec is as follows:

              void exec2() {
                   return _execve();
              }
              int exec() {
                   return fork(exec2);
              }

RETURN VALUE

       exec  returns the process ID of the child, or -1 (and setting errno) if
       an error occurs in either the fork or _execve call.

BUGS

       See the BUGS section in the execve(2) man page.

       If an error occurs in the _execve phase of this call, it  can  only  be
       detected  with  the wait(2) system call; it will get the return code of
       the process, which will be -1 if the _execve fails.

SEE ALSO

       execve(2), fork(2), wait(2), execl(3), system(3).



GNO                             19 January 1997                        EXEC(3)