.\" .\" 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. .\" .\" $Id: ld.1,v 1.4 1996/10/08 01:20:02 michaels Exp $ .\" .Dd October 14, 1993 .Dt LD 1 .Os .Sh NAME .Nm ld .Nd link editor .Sh SYNOPSIS .Nm ld .Op Fl MNnrSstXxz .Bk -words .Op Fl A Ar symbol-file .Op Fl assert Ar keyword .Op Fl B Ns Ar linkmode .Op Fl D Ar datasize .Op Fl d Ar c .Op Fl d Ar 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: .Pp .Bl -tag -width indent .It Fl A Ar symbol-file The 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 B Ns Ar dynamic Specifies that linking against dynamic libraries can take place. If a library specifier of the form -lx appears on the command line, .Nm ld searches for a library of the from libx.so.n.m .Po see the \& .Fl l option .Pc according to the search rules in effect. If such a file can not be found a traditional archive is looked for. This options can appear anywhere on the command line and is complementary to .Fl B Ns Ar static . .It Fl B Ns Ar static The counterpart of .Fl B Ns Ar dynamic . This option turns off dynamic linking for all library specifiers until a .Fl B Ns Ar dynamic 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 B Ns Ar shareable Instructs the linker to build a shared object from the object files rather than a normal executable image. .It Fl B Ns Ar symbolic 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, ie. translation with respect to the load address. Failure to resolve any symbolic reference causes an error to be reported. .It Fl B Ns Ar forcearchive 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 B Ns Ar silly Search for .Em \.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 Ar c Force allocation of commons even producing relocatable output. .It Fl d Ar 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-symbol 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 .Ar -l option. .It Fl l Ns Ar lib-spec This option specifies a library to be considered for inclusion in the output. If the .Fl B Ns Ar dynamic option is in effect, a shared library of the form lib.so.m.n .Po where \& .Em m is the major, and .Em n is the minor version number, respectively .Pc is searched for first. The library with the highest version found in the search path is selected. If no shared library is found or the .Fl B Ns Ar static option is in effect, an archive of the form 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 a .Dv OMAGIC output file. .It Fl n Produce a .Dv NMAGIC output file. .It Fl nostdlib Do not search the built-in path .Po usually .Dq /usr/lib .Pc for .Fl l specified libraries. .It Fl o Ar filename Specifies the name of the output file. Defaults to .Dq a.out . .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 Record the given path within the executable for run-time libary 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 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 libaries compatible with other operating systems. Eg. 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. .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 ldconfig 1 , .Xr ld.so 1 , .Xr link 5 .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 .Dq -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. .Sh HISTORY The shared library model employed by .Nm ld appeared first in SunOS 4.0.