.\" $OpenBSD: ld.1,v 1.18 2007/05/31 19:19:24 jmc Exp $ .\" $NetBSD: ld.1,v 1.14 1998/02/20 03:12:50 jonathan Exp $ .\" .\" Copyright (c) 1993 Paul Kranenburg .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by Paul Kranenburg. .\" 3. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" .Dd $Mdocdate: May 31 2007 $ .Dt LD 1 .Os .Sh NAME .Nm ld .Nd link editor .Sh SYNOPSIS .Nm ld .Op Fl MNnprSstXxZz .Bk -words .Op Fl A Ar symbol-file .Op Fl assert Ar keyword .Op Fl B Ns Ar linkmode .Op Fl D Ar data-size .Op Fl d\ c .Op Fl d\ p .Op Fl e Ar entry .Op Fl l Ns Ar library-specifier .Op Fl L Ns Ar library-search-path .Op Fl R Ns Ar record-library-search-path .Op Fl nostdlib .Op Fl o Ar filename .Op Fl T Ar address .Op Fl u Ar symbol .Op Fl V Ar shlib-version .Op Fl y Ar symbol .Ek .Sh DESCRIPTION .Nm combines the object and archive files given on the command line into a new object file. The output object file is either an executable program, a shared object suitable for loading at run-time, or an object file that can once again be processed by .Nm ld . Object files and archives are processed in the order given on the command line. .Pp The options are as follows: .Bl -tag -width Ds .It Fl A Ar symbol-file The symbol-file is taken as a base for link-editing the object files on the command line. .It Fl assert Ar keyword This option has currently no effect. It is here for compatibility with SunOS ld. All conditions which would cause a Sun assertion to fail will currently always cause error or warning messages from .Nm ld . .It Fl Bdynamic Specifies that linking against dynamic libraries can take place. If a library specifier of the form .Fl l Ns Ar spec appears on the command line, .Nm ld searches for a library of the from .Pa lib.so.. (see the .Fl l option) according to the search rules in effect. If such a file can not be found a traditional archive is looked for. This option can appear anywhere on the command line and is complementary to .Fl Bstatic . .It Fl Bstatic The counterpart of .Fl Bdynamic . This option turns off dynamic linking for all library specifiers until a .Fl Bdynamic is once again given. Any explicitly mentioned shared object encountered on the command line while this option is in effect is flagged as an error. .It Fl Bshareable Instructs the linker to build a shared object from the object files rather than a normal executable image. .It Fl Bsymbolic This option causes all symbolic references in the output to be resolved in this link-edit session. The only remaining run-time relocation requirements are .Em base-relative relocations, i.e. translation with respect to the load address. Failure to resolve any symbolic reference causes an error to be reported. .It Fl Bforcearchive Force all members of archives to be loaded, whether or not such members contribute a definition to any plain object files. Useful for making a shared library from an archive of PIC objects without having to unpack the archive. .It Fl Bsilly Search for .Pa \.sa silly archive companions of shared objects. Useful for compatibility with version 3 shared objects. .It Fl D Ar data-size Set the size of the data segment. For sanity's sake, this should be larger than the cumulative data sizes of the input files. .It Fl d\ c Force allocation of commons even producing relocatable output. .It Fl d\ p Force alias definitions of procedure calls in non-PIC code. Useful to obtain shareable code in the presence of run-time relocations as such calls will be re-directed through the Procedure Linkage Table (see .Xr link 5 . ) .It Fl e Ar entry Specifies the entry symbol for an executable. .It Fl L Ns Ar path Add .Ar path to the list of directories to search for libraries specified with the .Fl l option. .It Fl l Ns Ar spec This option specifies a library to be considered for inclusion in the output. If the .Fl Bdynamic option is in effect, a shared library of the form .Pa lib.so.. is searched for first (where .Em m is the major, and .Em n is the minor version number, respectively.) The library with the highest version found in the search path is selected. If no shared library is found or the .Fl Bstatic option is in effect, an archive of the form .Pa lib.a is looked for in the library search path. .It Fl M Produce output about the mapping of segments of the input files and the values assigned to .Pq global symbols in the output file. .It Fl N Produce an .Dv OMAGIC output file. .It Fl n Produce an .Dv NMAGIC output file. .It Fl nostdlib Do not search the built-in path .Po usually .Dq Pa /usr/lib .Pc for .Fl l specified libraries. .It Fl o Ar filename Specifies the name of the output file. Defaults to .Dq Pa a.out . .It Fl p Make the data segment start on a page boundary. .It Fl Q Produce a .Dv QMAGIC output file. .It Fl r Produce relocatable object file, suitable for another pass through .Nm ld . .It Fl R Ns Ar path Record .Ar path within the executable for run-time library search. This only applies to dynamically linked executables. .It Fl S Strip all debugger symbols from the output. .It Fl s Strip all symbols from the output. .It Fl T Ar address Specifies the start address of the text segment, with respect to which all input files will be relocated. .It Fl t Leave a trace of the input files as they are processed. .It Fl u Ar symbol Force .Ar symbol to be marked as undefined. Useful to force loading of an archive member in the absence of any other references to that member. .It Fl V Ar version Put the given version number into the output shared library .Pq if one is created . Useful to make shared libraries compatible with other operating systems, e.g. SunOS 4.x libraries use version number 3. Defaults to 8. .It Fl X Discard local symbols in the input files that start with the letter .Dq L . .It Fl x Discard all local symbols in the input files. .It Fl y Ar symbol Trace the manipulations inflicted on .Ar symbol . .It Fl z Make a .Dv ZMAGIC output file. This is the default. .It Fl Z Make an old-style .Dv ZMAGIC output file. This means no flags and no machine ID in the magic. .El .Pp The following long options are exceptions to the normal option syntax described above, and are provided for compatibility with later versions of GNU .Nm ld : .Bl -tag -width indent .It Fl rpath Ar path Record the given .Ar path within the executable for run-time library search, as for .Fl R . This only applies to dynamically linked executables. .It Fl shared Instructs the linker to build a shared object from the object files rather than a normal executable image. .It Fl soname Ar library-name This option and its .Ar library-name argument are ignored. They are provided for compatibility with versions of .Nm ld which allow the user to specify an internal name and version number for dynamically-linked shared libraries. .It Fl \&-whole-archive A positional qualifier to force loading from archives. For each archive mentioned on the commandline after this option, include every object file from the archive in the link, rather than searching the archive for the required object files. This is normally used when building shared libraries. .Pp The positional syntax is not currently implemented; .Fl \&-whole-archive is treated exactly as .Fl Bforcearchive . .It Fl \&-no-whole-archive This option should turn off the effect of a preceding .Fl \&-whole-archive for any subsequent archive files on the command line. It is currently ignored. .El .Sh ENVIRONMENT .Nm utilizes the following environment variables: .Bl -tag -width "LD_LIBRARY_PATH" .It Ev LD_LIBRARY_PATH This colon-separated list of directories is inserted into the search path for libraries following any directories specified via .Fl L options and preceding the built-in path. .It Ev LD_NOSTD_PATH When set, do not search the built-in path for libraries. This is an alternative to the .Fl nostdlib command-line flag. .El .\" .Sh FILES .Sh SEE ALSO .Xr ld.so 1 , .Xr link 5 , .Xr ldconfig 8 .Sh HISTORY The shared library model employed by .Nm ld appeared first in SunOS 4.0. .Sh CAVEATS An entry point must now explicitly be given if the output is intended to be a normal executable program. This was not the case for the previous version of .Nm ld . .Sh BUGS Shared objects are not properly checked for undefined symbols. .Pp Cascading of shared object defeats the .Fl Bstatic option. .Pp All shared objects presented to .Nm ld are marked for run-time loading in the output file, even if no symbols are needed from them.