1.\" $NetBSD: getprogname.3,v 1.4 2002/10/01 16:48:34 wiz Exp $ 2.\" 3.\" Copyright (c) 2001 Christopher G. Demetriou 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed for the 17.\" NetBSD Project. See http://www.netbsd.org/ for 18.\" information about NetBSD. 19.\" 4. The name of the author may not be used to endorse or promote products 20.\" derived from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32.\" 33.\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>> 34.\" 35.Dd February 11, 2001 36.Dt GETPROGNAME 3 37.Os 38.Sh NAME 39.Nm getprogname , 40.Nm setprogname 41.Nd get/set the name of the current program 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]stdlib.h\*[Gt] 46.Ft const char * 47.Fn getprogname "void" 48.Ft void 49.Fn setprogname "const char *name" 50.Sh DESCRIPTION 51These utility functions get and set the current program's name 52as used by various error-reporting functions. 53.Pp 54.Fn getprogname 55returns the name of the current program. 56This function is typically useful when generating error messages 57or other diagnostic output. 58If the program name has not been set, 59.Fn getprogname 60will return 61.Dv NULL . 62.Pp 63.Fn setprogname 64sets the name of the current program to be the last pathname 65component of the 66.Fa name 67argument. 68It should be invoked at the start of the program, using the 69.Fa argv[0] 70passed into the program's 71.Fn main 72function. 73A pointer into the string pointed to by the 74.Fa name 75argument is kept as the program name. 76Therefore, the string pointed to by 77.Fa name 78should not be modified during the rest of the program's operation. 79.Pp 80A program's name can only be set once, and in 81.Nx 82that is actually 83done by program start-up code that is run before 84.Fn main 85is called. 86Therefore, in 87.Nx , 88calling 89.Fn setprogname 90from 91.Fn main 92has no effect. 93However, it does serve to increase the portability of the program: 94on other operating systems, 95.Fn getprogname 96and 97.Fn setprogname 98may be implemented by a portability library, and a call to 99.Fn setprogname 100allows that library to know the program name without 101modifications to that system's program start-up code. 102.Sh SEE ALSO 103.Xr err 3 , 104.Xr setproctitle 3 105.Sh HISTORY 106The 107.Nm getprogname 108and 109.Nm setprogname 110function calls appeared in 111.Nx 1.6 . 112