1.\" 2.\" Copyright (c) 2001 Christopher G. Demetriou 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed for the 16.\" NetBSD Project. See http://www.netbsd.org/ for 17.\" information about NetBSD. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.\" $FreeBSD$ 33.\" 34.Dd April 18, 2021 35.Dt GETPROGNAME 3 36.Os 37.Sh NAME 38.Nm getprogname , 39.Nm setprogname 40.Nd get or set the program name 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In stdlib.h 45.Ft const char * 46.Fn getprogname "void" 47.Ft void 48.Fn setprogname "const char *progname" 49.Sh DESCRIPTION 50The 51.Fn getprogname 52and 53.Fn setprogname 54functions manipulate the name of the current program. 55They are used by error-reporting routines to produce 56consistent output. 57.Pp 58The 59.Fn getprogname 60function returns the name of the program. 61If the name has not been set yet, it will return 62.Dv NULL . 63.Pp 64The 65.Fn setprogname 66function sets the name of the program to be the last component of the 67.Fa progname 68argument. 69Since a pointer to the given string is kept as the program name, 70it should not be modified for the rest of the program's lifetime. 71.Pp 72In 73.Fx , 74the name of the program is set by the start-up code that is run before 75.Fn main ; 76thus, 77running 78.Fn setprogname 79is not necessary. 80Programs that desire maximum portability should still call it; 81on another operating system, 82these functions may be implemented in a portability library. 83Calling 84.Fn setprogname 85allows the aforementioned library to learn the program name without 86modifications to the start-up code. 87.Sh EXAMPLES 88The following example presents a simple program, which shows the difference 89between 90.Fn getprogname 91and 92.Va "argv[0]" . 93.Bd -literal -offset indent 94#include <stdio.h> 95#include <stdlib.h> 96 97int 98main(int argc, char** argv) 99{ 100 printf("getprogname(): %s\en", getprogname()); 101 printf("argv[0]: %s\en", argv[0]); 102 return (0); 103} 104.Ed 105.Pp 106When compiled and executed (e.g., with 107.Ql ./a.out ) 108the output of the program is going to look like this: 109.Bd -literal -offset indent 110getprogname(): a.out 111argv[0]: ./a.out 112.Ed 113.Sh SEE ALSO 114.Xr err 3 , 115.Xr setproctitle 3 116.Sh HISTORY 117These functions first appeared in 118.Nx 1.6 , 119and made their way into 120.Fx 4.4 . 121