mirror of https://github.com/GnoConsortium/gno.git
82 lines
1.6 KiB
Groff
82 lines
1.6 KiB
Groff
.\"
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.\" $Id: exec.3,v 1.1 1997/02/27 07:32:22 gdr Exp $
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.\"
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.TH EXEC 3 "19 January 1997" GNO "Library Routines"
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.SH NAME
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.BR exec
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\- load an executable file and launch as a new process
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.SH SYNOPSIS
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#include <unistd.h>
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.sp 1
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int
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\fBexec\fR(const char *\fIpathname\fR, const char *\fIcmdline\fR);
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.SH DESCRIPTION
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This call is provided only for backward compatibility and should be
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avoided. New programs should use the
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.BR execve (2)
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family of calls, the
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.BR system (3)
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routine, or the
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.BR EXECUTE
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shell call.
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.LP
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.BR exec
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is an alternative method for launching a new process under GNO.
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It is a combination of the
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.BR fork (2)
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and
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.BR _execve (2)
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system calls, and is in fact written in terms of them. The difference
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between
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.BR exec
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and
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.BR _execve
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is that
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.BR exec
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returns in all cases; it is a simplified interface for those who don't
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need to affect process information before a new executable begins
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(such as process group IDs or I/O redirection information).
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.LP
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The (somewhat simplified) algorithm for
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.BR exec
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is as follows:
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.RS
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.nf
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void exec2() {
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return _execve();
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}
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int exec() {
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return fork(exec2);
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}
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.fi
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.RE
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.SH RETURN VALUE
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.BR exec
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returns the process ID of the child, or -1 (and setting
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.BR errno )
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if an error occurs in either the
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.BR fork
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or
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.BR _execve
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call.
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.SH BUGS
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See the BUGS section in the
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.BR execve (2)
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man page.
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.LP
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If an error occurs in the
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.BR _execve
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phase of this call, it can only be detected with the
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.BR wait (2)
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system call; it will get the return code of the process, which will be -1
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if the
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.BR _execve
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fails.
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.SH SEE ALSO
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.BR execve (2),
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.BR fork (2),
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.BR wait (2),
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.BR execl (3),
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.BR system (3).
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