1.\" Copyright (c) 1998 John D. Polstra 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/lib/libc/gen/getobjformat.3,v 1.3.2.6 2003/03/13 18:05:37 trhodes Exp $ 26.\" $DragonFly: src/lib/libc/gen/getobjformat.3,v 1.2 2003/06/17 04:26:42 dillon Exp $ 27.\" 28.Dd September 7, 1998 29.Dt GETOBJFORMAT 3 30.Os 31.Sh NAME 32.Nm getobjformat 33.Nd get preferred object file format 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In objformat.h 38.Ft int 39.Fn getobjformat "char *buf" "size_t bufsize" "int *argcp" "char **argv" 40.Sh DESCRIPTION 41The 42.Fn getobjformat 43function 44queries several sources to determine the preferred object file 45format, and copies its name into a buffer provided by the caller. 46.Pp 47The object file format is determined as follows. If 48.Va argv 49is 50.No non- Ns Ev NULL 51and an explicit command line argument such as 52.Fl aout 53or 54.Fl elf 55is present, then that determines the object file format. 56.Pp 57Otherwise, if the variable 58.Ev OBJFORMAT 59is set in the environment, the object file format is taken from its 60value. 61.Pp 62Otherwise, if the file 63.Pa /etc/objformat 64is readable and contains a line of the form 65.Ql OBJFORMAT=xxx , 66the object file format is taken from there. 67.Pp 68Otherwise, a built-in system default object file format is returned. 69.Pp 70.Va buf 71points to a user-supplied buffer into which the name of the object 72file format is copied. 73.Va bufsize 74gives the size of the buffer in bytes. The string placed in 75.Va buf 76is always null-terminated. It is an error if the buffer is too 77small to hold the null-terminated name. 78.Pp 79.Va argv 80points to a 81.Dv NULL Ns -terminated 82argument vector to be scanned for object 83format options. 84.Va argv 85may be 86.Dv NULL , 87in which case the argument vector is not scanned. 88.Pp 89If 90.Va argcp 91is non-NULL, any object format options are deleted from the 92argument vector, and the updated argument count is stored into 93the integer referenced by 94.Va argcp . 95If 96.Va argcp 97is 98.Dv NULL , 99the argument vector is left unchanged. 100.Sh RETURN VALUES 101On success, 102.Fn getobjformat 103returns the length of the object file format name, not counting the 104null terminator. 105If the supplied buffer is too small to hold the object file format 106and its null terminator, 107.Fn getobjformat 108returns -1. In that case, the contents of the buffer and argument 109vector supplied by the caller are indeterminate. 110.Sh ENVIRONMENT 111.Bl -tag -width OBJFORMAT 112.It Ev OBJFORMAT 113If the environment variable 114.Ev OBJFORMAT 115is set, it overrides the default object file format. 116.Ev OBJFORMAT takes precedence over 117.Pa /etc/objformat . 118.El 119.Sh FILES 120.Bl -tag -width /etc/objformat -compact 121.It Pa /etc/objformat 122If present, specifies the object file format to use. Syntax is 123.Ql OBJFORMAT=xxx . 124.El 125.Sh SEE ALSO 126.Xr objformat 1 127.Sh HISTORY 128The 129.Fn getobjformat 130function first appeared in 131.Fx 3.0 . 132