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]
[--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]
[-k|--kill-at]
[-A|--add-stdcall-alias]
[-p|--ext-prefix-alias prefix]
[-x|--no-idata4] [-c|--no-idata5] [-i|--interwork]
[-n|--nodelete] [-t|--temp-prefix prefix]
[-v|--verbose]
[-h|--help] [-V|--version]
[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:
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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. This file can be created by giving
the -l option to dlltool when it is creating or reading in a
.def file.
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
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.
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-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.
--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
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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 the
exported functions.
-k
--kill-at
Specifies that when dlltool is creating the exports file
it should not append the string @ <number>. These
numbers are called ordinal numbers and they represent
another way of accessing the function in a DLL, other
than by name.
-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>.
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-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.
-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
--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.
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DLLTOOL(1) GNU Development Tools DLLTOOL(1)
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