dlltool(1)
DLLTOOL(1) GNU Development Tools DLLTOOL(1)
NAME
dlltool - Create files needed to build and use DLLs.
SYNOPSIS
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]
[object-file ...]
DESCRIPTION
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.
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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
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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.
OPTIONS
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.
--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.
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--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
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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
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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.
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-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.
SEE ALSO
The Info pages for binutils.
COPYRIGHT
Copyright (c) 1991-2018 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".
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