1 @node Visual Studio Compatibility
2 @section Visual Studio Compatibility
6 The @code{lib-msvc-compat} module detects whether the linker supports
7 @code{--output-def} when building a library. That parameter is used
8 to generate a DEF file for a shared library (DLL). DEF files are
9 useful for developers that use Visual Studio to develop programs that
10 links to your library. See the GNU LD manual for more information.
12 There are other ways to create a DEF file, but we believe they are all
13 sub-optimal to using @code{--output-def} during the build process.
14 The variants we have considered include:
17 @item Use DUMPBIN /EXPORTS.
18 This is explained in @url{https://support.microsoft.com/kb/131313/en-us}.
19 The tool does not generate DEF files directly, so its output needs to
20 be post processed manually:
23 dumpbin /EXPORTS libfoo-0.dll | tail -n+20 | awk '@{ print $4 @}'; \
25 $ lib /def:libfoo-0.def
29 There is a tool called IMPDEF
30 that can generate DEF files. However, it is not part of a standard
31 Visual Studio installation. Further, it is documented as being an
35 The dlltool is part of the MinGW suite, and thus not part of a
36 standard Visual Studio installation. The documentation for the IMPDEF
37 tool claims that DLLTOOL is the wrong tool for this job. Finally,
38 DLLTOOL does not generate DEF files directly, so it requires
39 post-processing of the output.
43 If you are using libtool to build your shared library, here is how to
44 use this module. Import @code{lib-msvc-compat} to your project, and
45 then add the following lines to the @code{Makefile.am} that builds the
50 libfoo_la_LDFLAGS += -Wl,--output-def,libfoo-$(DLL_VERSION).def
51 defexecdir = $(bindir)
52 defexec_DATA = libfoo-$(DLL_VERSION).def
53 DISTCLEANFILES += $(defexec_DATA)
57 The @code{DLL_VERSION} variable needs to be defined. It should be the
58 shared library version number used in the DLL filename. For Windows
59 targets you compute this value from the values you pass to Libtool's
60 @code{-version-info}. Assuming you have variables @code{LT_CURRENT}
61 and @code{LT_AGE} defined for the @code{CURRENT} and @code{AGE}
62 libtool version integers, you compute @code{DLL_VERSION} as follows:
65 DLL_VERSION=`expr $@{LT_CURRENT@} - $@{LT_AGE@}`