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.Dd April 18, 2021 33.Dt GETPROGNAME 3 34.Os 35.Sh NAME 36.Nm getprogname , 37.Nm setprogname 38.Nd get or set the program name 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In stdlib.h 43.Ft const char * 44.Fn getprogname "void" 45.Ft void 46.Fn setprogname "const char *progname" 47.Sh DESCRIPTION 48The 49.Fn getprogname 50and 51.Fn setprogname 52functions manipulate the name of the current program. 53They are used by error-reporting routines to produce 54consistent output. 55.Pp 56The 57.Fn getprogname 58function returns the name of the program. 59If the name has not been set yet, it will return 60.Dv NULL . 61.Pp 62The 63.Fn setprogname 64function sets the name of the program to be the last component of the 65.Fa progname 66argument. 67Since a pointer to the given string is kept as the program name, 68it should not be modified for the rest of the program's lifetime. 69.Pp 70In 71.Fx , 72the name of the program is set by the start-up code that is run before 73.Fn main ; 74thus, 75running 76.Fn setprogname 77is not necessary. 78Programs that desire maximum portability should still call it; 79on another operating system, 80these functions may be implemented in a portability library. 81Calling 82.Fn setprogname 83allows the aforementioned library to learn the program name without 84modifications to the start-up code. 85.Sh EXAMPLES 86The following example presents a simple program, which shows the difference 87between 88.Fn getprogname 89and 90.Va "argv[0]" . 91.Bd -literal -offset indent 92#include <stdio.h> 93#include <stdlib.h> 94 95int 96main(int argc, char** argv) 97{ 98 printf("getprogname(): %s\en", getprogname()); 99 printf("argv[0]: %s\en", argv[0]); 100 return (0); 101} 102.Ed 103.Pp 104When compiled and executed (e.g., with 105.Ql ./a.out ) 106the output of the program is going to look like this: 107.Bd -literal -offset indent 108getprogname(): a.out 109argv[0]: ./a.out 110.Ed 111.Sh SEE ALSO 112.Xr err 3 , 113.Xr setproctitle 3 114.Sh HISTORY 115These functions first appeared in 116.Nx 1.6 , 117and made their way into 118.Fx 4.4 . 119