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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT | COLOPHON |
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DLLTOOL(1) GNU Development Tools DLLTOOL(1)
dlltool - create files needed to build and use DLLs
dlltool [-d|--input-def def-file-name]
[-b|--base-file base-file-name]
[-e|--output-exp exports-file-name]
[-z|--output-def def-file-name]
[-l|--output-lib library-file-name]
[-y|--output-delaylib library-file-name]
[--export-all-symbols] [--no-export-all-symbols]
[--exclude-symbols list]
[--no-default-excludes]
[-S|--as path-to-assembler] [-f|--as-flags options]
[-D|--dllname name] [-m|--machine machine]
[-a|--add-indirect]
[-U|--add-underscore] [--add-stdcall-underscore]
[-k|--kill-at] [-A|--add-stdcall-alias]
[-p|--ext-prefix-alias prefix]
[-x|--no-idata4] [-c|--no-idata5]
[--use-nul-prefixed-import-tables]
[-I|--identify library-file-name] [--identify-strict]
[-i|--interwork]
[-n|--nodelete] [-t|--temp-prefix prefix]
[-v|--verbose]
[-h|--help] [-V|--version]
[--no-leading-underscore] [--leading-underscore]
[--deterministic-libraries]
[--non-deterministic-libraries]
[object-file ...]
dlltool reads its inputs, which can come from the -d and -b
options as well as object files specified on the command line. It
then processes these inputs and if the -e option has been
specified it creates a exports file. If the -l option has been
specified it creates a library file and if the -z option has been
specified it creates a def file. Any or all of the -e, -l and -z
options can be present in one invocation of dlltool.
When creating a DLL, along with the source for the DLL, it is
necessary to have three other files. dlltool can help with the
creation of these files.
The first file is a .def file which specifies which functions are
exported from the DLL, which functions the DLL imports, and so on.
This is a text file and can be created by hand, or dlltool can be
used to create it using the -z option. In this case dlltool will
scan the object files specified on its command line looking for
those functions which have been specially marked as being exported
and put entries for them in the .def file it creates.
In order to mark a function as being exported from a DLL, it needs
to have an -export:<name_of_function> entry in the .drectve
section of the object file. This can be done in C by using the
asm() operator:
asm (".section .drectve");
asm (".ascii \"-export:my_func\"");
int my_func (void) { ... }
The second file needed for DLL creation is an exports file. This
file is linked with the object files that make up the body of the
DLL and it handles the interface between the DLL and the outside
world. This is a binary file and it can be created by giving the
-e option to dlltool when it is creating or reading in a .def
file.
The third file needed for DLL creation is the library file that
programs will link with in order to access the functions in the
DLL (an `import library'). This file can be created by giving the
-l option to dlltool when it is creating or reading in a .def
file.
If the -y option is specified, dlltool generates a delay-import
library that can be used instead of the normal import library to
allow a program to link to the dll only as soon as an imported
function is called for the first time. The resulting executable
will need to be linked to the static delayimp library containing
__delayLoadHelper2(), which in turn will import LoadLibraryA and
GetProcAddress from kernel32.
dlltool builds the library file by hand, but it builds the exports
file by creating temporary files containing assembler statements
and then assembling these. The -S command-line option can be used
to specify the path to the assembler that dlltool will use, and
the -f option can be used to pass specific flags to that
assembler. The -n can be used to prevent dlltool from deleting
these temporary assembler files when it is done, and if -n is
specified twice then this will prevent dlltool from deleting the
temporary object files it used to build the library.
Here is an example of creating a DLL from a source file dll.c and
also creating a program (from an object file called program.o)
that uses that DLL:
gcc -c dll.c
dlltool -e exports.o -l dll.lib dll.o
gcc dll.o exports.o -o dll.dll
gcc program.o dll.lib -o program
dlltool may also be used to query an existing import library to
determine the name of the DLL to which it is associated. See the
description of the -I or --identify option.
The command-line options have the following meanings:
-d filename
--input-def filename
Specifies the name of a .def file to be read in and processed.
-b filename
--base-file filename
Specifies the name of a base file to be read in and processed.
The contents of this file will be added to the relocation
section in the exports file generated by dlltool.
-e filename
--output-exp filename
Specifies the name of the export file to be created by
dlltool.
-z filename
--output-def filename
Specifies the name of the .def file to be created by dlltool.
-l filename
--output-lib filename
Specifies the name of the library file to be created by
dlltool.
-y filename
--output-delaylib filename
Specifies the name of the delay-import library file to be
created by dlltool.
--deterministic-libraries
--non-deterministic-libraries
When creating output libraries in response to either the
--output-lib or --output-delaylib options either use the value
of zero for any timestamps, user ids and group ids created
(--deterministic-libraries) or the actual timestamps, user ids
and group ids (--non-deterministic-libraries).
--export-all-symbols
Treat all global and weak defined symbols found in the input
object files as symbols to be exported. There is a small list
of symbols which are not exported by default; see the
--no-default-excludes option. You may add to the list of
symbols to not export by using the --exclude-symbols option.
--no-export-all-symbols
Only export symbols explicitly listed in an input .def file or
in .drectve sections in the input object files. This is the
default behaviour. The .drectve sections are created by
dllexport attributes in the source code.
--exclude-symbols list
Do not export the symbols in list. This is a list of symbol
names separated by comma or colon characters. The symbol
names should not contain a leading underscore. This is only
meaningful when --export-all-symbols is used.
--no-default-excludes
When --export-all-symbols is used, it will by default avoid
exporting certain special symbols. The current list of
symbols to avoid exporting is DllMain@12, DllEntryPoint@0,
impure_ptr. You may use the --no-default-excludes option to
go ahead and export these special symbols. This is only
meaningful when --export-all-symbols is used.
-S path
--as path
Specifies the path, including the filename, of the assembler
to be used to create the exports file.
-f options
--as-flags options
Specifies any specific command-line options to be passed to
the assembler when building the exports file. This option
will work even if the -S option is not used. This option only
takes one argument, and if it occurs more than once on the
command line, then later occurrences will override earlier
occurrences. So if it is necessary to pass multiple options
to the assembler they should be enclosed in double quotes.
-D name
--dll-name name
Specifies the name to be stored in the .def file as the name
of the DLL when the -e option is used. If this option is not
present, then the filename given to the -e option will be used
as the name of the DLL.
-m machine
-machine machine
Specifies the type of machine for which the library file
should be built. dlltool has a built in default type,
depending upon how it was created, but this option can be used
to override that. This is normally only useful when creating
DLLs for an ARM processor, when the contents of the DLL are
actually encode using Thumb instructions.
-a
--add-indirect
Specifies that when dlltool is creating the exports file it
should add a section which allows the exported functions to be
referenced without using the import library. Whatever the
hell that means!
-U
--add-underscore
Specifies that when dlltool is creating the exports file it
should prepend an underscore to the names of all exported
symbols.
--no-leading-underscore
--leading-underscore
Specifies whether standard symbol should be forced to be
prefixed, or not.
--add-stdcall-underscore
Specifies that when dlltool is creating the exports file it
should prepend an underscore to the names of exported stdcall
functions. Variable names and non-stdcall function names are
not modified. This option is useful when creating
GNU-compatible import libs for third party DLLs that were
built with MS-Windows tools.
-k
--kill-at
Specifies that @<number> suffixes should be omitted from the
names of stdcall functions that will be imported from the DLL.
This is useful when creating an import library for a DLL which
exports stdcall functions but without the usual @<number>
symbol name suffix.
This does not change the naming of symbols provided by the
import library to programs linked against it, but only the
entries in the import table (ie the .idata section).
-A
--add-stdcall-alias
Specifies that when dlltool is creating the exports file it
should add aliases for stdcall symbols without @ <number> in
addition to the symbols with @ <number>.
-p
--ext-prefix-alias prefix
Causes dlltool to create external aliases for all DLL imports
with the specified prefix. The aliases are created for both
external and import symbols with no leading underscore.
-x
--no-idata4
Specifies that when dlltool is creating the exports and
library files it should omit the ".idata4" section. This is
for compatibility with certain operating systems.
--use-nul-prefixed-import-tables
Specifies that when dlltool is creating the exports and
library files it should prefix the ".idata4" and ".idata5" by
zero an element. This emulates old gnu import library
generation of "dlltool". By default this option is turned off.
-c
--no-idata5
Specifies that when dlltool is creating the exports and
library files it should omit the ".idata5" section. This is
for compatibility with certain operating systems.
-I filename
--identify filename
Specifies that dlltool should inspect the import library
indicated by filename and report, on "stdout", the name(s) of
the associated DLL(s). This can be performed in addition to
any other operations indicated by the other options and
arguments. dlltool fails if the import library does not exist
or is not actually an import library. See also
--identify-strict.
--identify-strict
Modifies the behavior of the --identify option, such that an
error is reported if filename is associated with more than one
DLL.
-i
--interwork
Specifies that dlltool should mark the objects in the library
file and exports file that it produces as supporting
interworking between ARM and Thumb code.
-n
--nodelete
Makes dlltool preserve the temporary assembler files it used
to create the exports file. If this option is repeated then
dlltool will also preserve the temporary object files it uses
to create the library file.
-t prefix
--temp-prefix prefix
Makes dlltool use prefix when constructing the names of
temporary assembler and object files. By default, the temp
file prefix is generated from the pid.
-v
--verbose
Make dlltool describe what it is doing.
-h
--help
Displays a list of command-line options and then exits.
-V
--version
Displays dlltool's version number and then exits.
@file
Read command-line options from file. The options read are
inserted in place of the original @file option. If file does
not exist, or cannot be read, then the option will be treated
literally, and not removed.
Options in file are separated by whitespace. A whitespace
character may be included in an option by surrounding the
entire option in either single or double quotes. Any
character (including a backslash) may be included by prefixing
the character to be included with a backslash. The file may
itself contain additional @file options; any such options will
be processed recursively.
The Info pages for binutils.
Copyright (c) 1991-2025 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with no Invariant Sections, with no Front-Cover Texts,
and with no Back-Cover Texts. A copy of the license is included
in the section entitled "GNU Free Documentation License".
This page is part of the binutils (a collection of tools for
working with executable binaries) project. Information about the
project can be found at ⟨http://www.gnu.org/software/binutils/⟩.
If you have a bug report for this manual page, see
⟨http://sourceware.org/bugzilla/enter_bug.cgi?product=binutils⟩.
This page was obtained from the tarball binutils-2.44.tar.gz
fetched from ⟨https://ftp.gnu.org/gnu/binutils/⟩ on 2025-02-02.
If you discover any rendering problems in this HTML version of the
page, or you believe there is a better or more up-to-date source
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manual page), send a mail to man-pages@man7.org
binutils-2.44 2025-02-02 DLLTOOL(1)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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