NetBSD/lib/libc/gen/getprogname.3

.\" $NetBSD: getprogname.3,v 1.6 2003/07/26 19:24:42 salo Exp $
.\"
.\" Copyright (c) 2001 Christopher G. Demetriou
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"          This product includes software developed for the
.\"          NetBSD Project.  See http://www.NetBSD.org/ for
.\"          information about NetBSD.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
.\"
.Dd February 11, 2001
.Dt GETPROGNAME 3
.Os
.Sh NAME
.Nm getprogname ,
.Nm setprogname
.Nd get/set the name of the current program
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft const char *
.Fn getprogname "void"
.Ft void
.Fn setprogname "const char *name"
.Sh DESCRIPTION
These utility functions get and set the current program's name
as used by various error-reporting functions.
.Pp
.Fn getprogname
returns the name of the current program.
This function is typically useful when generating error messages
or other diagnostic output.
If the program name has not been set,
.Fn getprogname
will return
.Dv NULL .
.Pp
.Fn setprogname
sets the name of the current program to be the last pathname
component of the
.Fa name
argument.
It should be invoked at the start of the program, using the
.Fa argv[0]
passed into the program's
.Fn main
function.
A pointer into the string pointed to by the
.Fa name
argument is kept as the program name.
Therefore, the string pointed to by
.Fa name
should not be modified during the rest of the program's operation.
.Pp
A program's name can only be set once, and in
.Nx
that is actually
done by program start-up code that is run before
.Fn main
is called.
Therefore, in
.Nx ,
calling
.Fn setprogname
from
.Fn main
has no effect.
However, it does serve to increase the portability of the program:
on other operating systems,
.Fn getprogname
and
.Fn setprogname
may be implemented by a portability library, and a call to
.Fn setprogname
allows that library to know the program name without
modifications to that system's program start-up code.
.Sh SEE ALSO
.Xr err 3 ,
.Xr setproctitle 3
.Sh HISTORY
The
.Nm getprogname
and
.Nm setprogname
function calls appeared in
.Nx 1.6 .