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.\" 27.Dd September 7, 1998 28.Dt GETOBJFORMAT 3 29.Os 30.Sh NAME 31.Nm getobjformat 32.Nd get preferred object file format 33.Sh LIBRARY 34.Lb libc 35.Sh SYNOPSIS 36.In objformat.h 37.Ft int 38.Fn getobjformat "char *buf" "size_t bufsize" "int *argcp" "char **argv" 39.Sh DESCRIPTION 40The 41.Fn getobjformat 42function 43queries several sources to determine the preferred object file 44format, and copies its name into a buffer provided by the caller. 45.Pp 46The object file format is determined as follows. If 47.Va argv 48is 49.No non- Ns Ev NULL 50and an explicit command line argument such as 51.Fl aout 52or 53.Fl elf 54is present, then that determines the object file format. 55.Pp 56Otherwise, if the variable 57.Ev OBJFORMAT 58is set in the environment, the object file format is taken from its 59value. 60.Pp 61Otherwise, if the file 62.Pa /etc/objformat 63is readable and contains a line of the form 64.Ql OBJFORMAT=xxx , 65the object file format is taken from there. 66.Pp 67Otherwise, a built-in system default object file format is returned. 68.Pp 69.Va buf 70points to a user-supplied buffer into which the name of the object 71file format is copied. 72.Va bufsize 73gives the size of the buffer in bytes. The string placed in 74.Va buf 75is always null-terminated. It is an error if the buffer is too 76small to hold the null-terminated name. 77.Pp 78.Va argv 79points to a 80.Dv NULL Ns -terminated 81argument vector to be scanned for object 82format options. 83.Va argv 84may be 85.Dv NULL , 86in which case the argument vector is not scanned. 87.Pp 88If 89.Va argcp 90is non-NULL, any object format options are deleted from the 91argument vector, and the updated argument count is stored into 92the integer referenced by 93.Va argcp . 94If 95.Va argcp 96is 97.Dv NULL , 98the argument vector is left unchanged. 99.Sh RETURN VALUES 100On success, 101.Fn getobjformat 102returns the length of the object file format name, not counting the 103null terminator. 104If the supplied buffer is too small to hold the object file format 105and its null terminator, 106.Fn getobjformat 107returns -1. In that case, the contents of the buffer and argument 108vector supplied by the caller are indeterminate. 109.Sh ENVIRONMENT 110.Bl -tag -width OBJFORMAT 111.It Ev OBJFORMAT 112If the environment variable 113.Ev OBJFORMAT 114is set, it overrides the default object file format. 115.Ev OBJFORMAT takes precedence over 116.Pa /etc/objformat . 117.El 118.Sh FILES 119.Bl -tag -width /etc/objformat -compact 120.It Pa /etc/objformat 121If present, specifies the object file format to use. Syntax is 122.Ql OBJFORMAT=xxx . 123.El 124.Sh SEE ALSO 125.Xr objformat 1 126.Sh HISTORY 127The 128.Fn getobjformat 129function first appeared in 130.Fx 3.0 . 131