1DLLTOOL(1) GNU Development Tools DLLTOOL(1)
2
6 dlltool - create files needed to build and use DLLs
7
9 dlltool [-d|--input-def def-file-name]
10 [-b|--base-file base-file-name]
11 [-e|--output-exp exports-file-name]
12 [-z|--output-def def-file-name]
13 [-l|--output-lib library-file-name]
14 [-y|--output-delaylib library-file-name]
15 [--export-all-symbols] [--no-export-all-symbols]
16 [--exclude-symbols list]
17 [--no-default-excludes]
18 [-S|--as path-to-assembler] [-f|--as-flags options]
19 [-D|--dllname name] [-m|--machine machine]
20 [-a|--add-indirect]
21 [-U|--add-underscore] [--add-stdcall-underscore]
22 [-k|--kill-at] [-A|--add-stdcall-alias]
23 [-p|--ext-prefix-alias prefix]
24 [-x|--no-idata4] [-c|--no-idata5]
25 [--use-nul-prefixed-import-tables]
26 [-I|--identify library-file-name] [--identify-strict]
27 [-i|--interwork]
28 [-n|--nodelete] [-t|--temp-prefix prefix]
29 [-v|--verbose]
30 [-h|--help] [-V|--version]
31 [--no-leading-underscore] [--leading-underscore]
32 [object-file ...]
33
35 dlltool reads its inputs, which can come from the -d and -b options as
36 well as object files specified on the command line. It then processes
37 these inputs and if the -e option has been specified it creates a
38 exports file. If the -l option has been specified it creates a library
39 file and if the -z option has been specified it creates a def file.
40 Any or all of the -e, -l and -z options can be present in one
41 invocation of dlltool.
42 When creating a DLL, along with the source for the DLL, it is necessary
44 to have three other files. dlltool can help with the creation of these
45 files.
46 The first file is a .def file which specifies which functions are
48 exported from the DLL, which functions the DLL imports, and so on.
49 This is a text file and can be created by hand, or dlltool can be used
50 to create it using the -z option. In this case dlltool will scan the
51 object files specified on its command line looking for those functions
52 which have been specially marked as being exported and put entries for
53 them in the .def file it creates.
54 In order to mark a function as being exported from a DLL, it needs to
56 have an -export:<name_of_function> entry in the .drectve section of the
57 object file. This can be done in C by using the asm() operator:
58 asm (".section .drectve");
60 asm (".ascii \"-export:my_func\"");
61 int my_func (void) { ... }
63 The second file needed for DLL creation is an exports file. This file
65 is linked with the object files that make up the body of the DLL and it
66 handles the interface between the DLL and the outside world. This is a
67 binary file and it can be created by giving the -e option to dlltool
68 when it is creating or reading in a .def file.
69 The third file needed for DLL creation is the library file that
71 programs will link with in order to access the functions in the DLL (an
72 `import library'). This file can be created by giving the -l option to
73 dlltool when it is creating or reading in a .def file.
74 If the -y option is specified, dlltool generates a delay-import library
76 that can be used instead of the normal import library to allow a
77 program to link to the dll only as soon as an imported function is
78 called for the first time. The resulting executable will need to be
79 linked to the static delayimp library containing __delayLoadHelper2(),
80 which in turn will import LoadLibraryA and GetProcAddress from
81 kernel32.
82 dlltool builds the library file by hand, but it builds the exports file
84 by creating temporary files containing assembler statements and then
85 assembling these. The -S command-line option can be used to specify
86 the path to the assembler that dlltool will use, and the -f option can
87 be used to pass specific flags to that assembler. The -n can be used
88 to prevent dlltool from deleting these temporary assembler files when
89 it is done, and if -n is specified twice then this will prevent dlltool
90 from deleting the temporary object files it used to build the library.
91 Here is an example of creating a DLL from a source file dll.c and also
93 creating a program (from an object file called program.o) that uses
94 that DLL:
95 gcc -c dll.c
97 dlltool -e exports.o -l dll.lib dll.o
98 gcc dll.o exports.o -o dll.dll
99 gcc program.o dll.lib -o program
100 dlltool may also be used to query an existing import library to
102 determine the name of the DLL to which it is associated. See the
103 description of the -I or --identify option.
104
106 The command-line options have the following meanings:
107 -d filename
109 --input-def filename
110 Specifies the name of a .def file to be read in and processed.
111 -b filename
113 --base-file filename
114 Specifies the name of a base file to be read in and processed. The
115 contents of this file will be added to the relocation section in
116 the exports file generated by dlltool.
117 -e filename
119 --output-exp filename
120 Specifies the name of the export file to be created by dlltool.
121 -z filename
123 --output-def filename
124 Specifies the name of the .def file to be created by dlltool.
125 -l filename
127 --output-lib filename
128 Specifies the name of the library file to be created by dlltool.
129 -y filename
131 --output-delaylib filename
132 Specifies the name of the delay-import library file to be created
133 by dlltool.
134 --export-all-symbols
136 Treat all global and weak defined symbols found in the input object
137 files as symbols to be exported. There is a small list of symbols
138 which are not exported by default; see the --no-default-excludes
139 option. You may add to the list of symbols to not export by using
140 the --exclude-symbols option.
141 --no-export-all-symbols
143 Only export symbols explicitly listed in an input .def file or in
144 .drectve sections in the input object files. This is the default
145 behaviour. The .drectve sections are created by dllexport
146 attributes in the source code.
147 --exclude-symbols list
149 Do not export the symbols in list. This is a list of symbol names
150 separated by comma or colon characters. The symbol names should
151 not contain a leading underscore. This is only meaningful when
152 --export-all-symbols is used.
153 --no-default-excludes
155 When --export-all-symbols is used, it will by default avoid
156 exporting certain special symbols. The current list of symbols to
157 avoid exporting is DllMain@12, DllEntryPoint@0, impure_ptr. You
158 may use the --no-default-excludes option to go ahead and export
159 these special symbols. This is only meaningful when
160 --export-all-symbols is used.
161 -S path
163 --as path
164 Specifies the path, including the filename, of the assembler to be
165 used to create the exports file.
166 -f options
168 --as-flags options
169 Specifies any specific command-line options to be passed to the
170 assembler when building the exports file. This option will work
171 even if the -S option is not used. This option only takes one
172 argument, and if it occurs more than once on the command line, then
173 later occurrences will override earlier occurrences. So if it is
174 necessary to pass multiple options to the assembler they should be
175 enclosed in double quotes.
176 -D name
178 --dll-name name
179 Specifies the name to be stored in the .def file as the name of the
180 DLL when the -e option is used. If this option is not present,
181 then the filename given to the -e option will be used as the name
182 of the DLL.
183 -m machine
185 -machine machine
186 Specifies the type of machine for which the library file should be
187 built. dlltool has a built in default type, depending upon how it
188 was created, but this option can be used to override that. This is
189 normally only useful when creating DLLs for an ARM processor, when
190 the contents of the DLL are actually encode using Thumb
191 instructions.
192 -a
194 --add-indirect
195 Specifies that when dlltool is creating the exports file it should
196 add a section which allows the exported functions to be referenced
197 without using the import library. Whatever the hell that means!
198 -U
200 --add-underscore
201 Specifies that when dlltool is creating the exports file it should
202 prepend an underscore to the names of all exported symbols.
203 --no-leading-underscore
205 --leading-underscore
206 Specifies whether standard symbol should be forced to be prefixed,
207 or not.
208 --add-stdcall-underscore
210 Specifies that when dlltool is creating the exports file it should
211 prepend an underscore to the names of exported stdcall functions.
212 Variable names and non-stdcall function names are not modified.
213 This option is useful when creating GNU-compatible import libs for
214 third party DLLs that were built with MS-Windows tools.
215 -k
217 --kill-at
218 Specifies that @<number> suffixes should be omitted from the names
219 of stdcall functions that will be imported from the DLL. This is
220 useful when creating an import library for a DLL which exports
221 stdcall functions but without the usual @<number> symbol name
222 suffix.
223 This does not change the naming of symbols provided by the import
225 library to programs linked against it, but only the entries in the
226 import table (ie the .idata section).
227 -A
229 --add-stdcall-alias
230 Specifies that when dlltool is creating the exports file it should
231 add aliases for stdcall symbols without @ <number> in addition to
232 the symbols with @ <number>.
233 -p
235 --ext-prefix-alias prefix
236 Causes dlltool to create external aliases for all DLL imports with
237 the specified prefix. The aliases are created for both external
238 and import symbols with no leading underscore.
239 -x
241 --no-idata4
242 Specifies that when dlltool is creating the exports and library
243 files it should omit the ".idata4" section. This is for
244 compatibility with certain operating systems.
245 --use-nul-prefixed-import-tables
247 Specifies that when dlltool is creating the exports and library
248 files it should prefix the ".idata4" and ".idata5" by zero an
249 element. This emulates old gnu import library generation of
250 "dlltool". By default this option is turned off.
251 -c
253 --no-idata5
254 Specifies that when dlltool is creating the exports and library
255 files it should omit the ".idata5" section. This is for
256 compatibility with certain operating systems.
257 -I filename
259 --identify filename
260 Specifies that dlltool should inspect the import library indicated
261 by filename and report, on "stdout", the name(s) of the associated
262 DLL(s). This can be performed in addition to any other operations
263 indicated by the other options and arguments. dlltool fails if the
264 import library does not exist or is not actually an import library.
265 See also --identify-strict.
266 --identify-strict
268 Modifies the behavior of the --identify option, such that an error
269 is reported if filename is associated with more than one DLL.
270 -i
272 --interwork
273 Specifies that dlltool should mark the objects in the library file
274 and exports file that it produces as supporting interworking
275 between ARM and Thumb code.
276 -n
278 --nodelete
279 Makes dlltool preserve the temporary assembler files it used to
280 create the exports file. If this option is repeated then dlltool
281 will also preserve the temporary object files it uses to create the
282 library file.
283 -t prefix
285 --temp-prefix prefix
286 Makes dlltool use prefix when constructing the names of temporary
287 assembler and object files. By default, the temp file prefix is
288 generated from the pid.
289 -v
291 --verbose
292 Make dlltool describe what it is doing.
293 -h
295 --help
296 Displays a list of command-line options and then exits.
297 -V
299 --version
300 Displays dlltool's version number and then exits.
301 @file
303 Read command-line options from file. The options read are inserted
304 in place of the original @file option. If file does not exist, or
305 cannot be read, then the option will be treated literally, and not
306 removed.
307 Options in file are separated by whitespace. A whitespace
309 character may be included in an option by surrounding the entire
310 option in either single or double quotes. Any character (including
311 a backslash) may be included by prefixing the character to be
312 included with a backslash. The file may itself contain additional
313 @file options; any such options will be processed recursively.
314
316 The Info pages for binutils.
317
319 Copyright (c) 1991-2022 Free Software Foundation, Inc.
320 Permission is granted to copy, distribute and/or modify this document
322 under the terms of the GNU Free Documentation License, Version 1.3 or
323 any later version published by the Free Software Foundation; with no
324 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
325 Texts. A copy of the license is included in the section entitled "GNU
326 Free Documentation License".
327binutils-2.39 2023-06-08 DLLTOOL(1)