Take the following C test code. I want to make a DLL which exports stdcall
HelloWorld function.
test.c:
__attribute__((dllexport)) void __attribute__((__stdcall__)) HelloWorld()
{
}
Compiling & linking it gives the following error during linking with GCC 4.3.0,
while it works fine with GCC 3.4.5.
$ i586-mingw32msvc-gcc -c -o test.o test.c
$ i586-mingw32msvc-gcc -shared -o test.dll test.o
Cannot export HelloWorld: symbol not found
collect2: ld returned 1 exit status
Examining the object file seems to reveal the problem, especially when compared
to the GCC 3.4.5 mingw crosscompiler which is in Debian.
GCC 4.3.0:
$ i586-mingw32msvc-nm test.o | grep HelloWorld
00000000 T [EMAIL PROTECTED]
$ strings test.o | grep HelloWorld
-export:HelloWorld
[EMAIL PROTECTED]
GCC 3.4.5:
$ i586-mingw32msvc-nm test.o | grep HelloWorld
00000000 T [EMAIL PROTECTED]
$ strings test.o | grep HelloWorld
-export:[EMAIL PROTECTED]
[EMAIL PROTECTED]
Notice the subtle difference in output of the last command. Between 3.4.5 and
4.3.0 the @0 stdcall decoration in the -export:[EMAIL PROTECTED] line got lost,
which makes it impossible to link DLLs with exported stdcall functions.
Here are some details about the compiler versions used for testing:
$ i586-mingw32msvc-gcc-4.3.0 -v
Using built-in specs.
Target: i586-mingw32msvc
Configured with: ../gcc/configure --prefix=/opt/mingw --target=i586-mingw32msvc
--enable-languages=c --disable-multilib --disable-shared --enable-threads=win32
--enable-version-specific-runtime-libs --enable-sjlj-exceptions :
(reconfigured) ../gcc/configure --prefix=/opt/mingw --target=i586-mingw32msvc
--enable-languages=c,c++ --disable-multilib --disable-shared
--enable-threads=win32 --enable-version-specific-runtime-libs
--enable-sjlj-exceptions
Thread model: win32
gcc version 4.3.0 20070424 (experimental)
$ i586-mingw32msvc-gcc-3.4.5 -v
Reading specs from /usr/lib/gcc/i586-mingw32msvc/3.4.5/specs
Configured with:
/build/buildd/mingw32-3.4.5.20060117.1.dfsg/build_dir/src/gcc-3.4.5-20060117-1-dfsg/configure
-v --prefix=/usr --target=i586-mingw32msvc --enable-languages=c,c++
--enable-threads --enable-sjlj-exceptions --disable-multilib
--enable-version-specific-runtime-libs
Thread model: win32
gcc version 3.4.5 (mingw special)
--
Summary: Cannot create DLL with exported stdcall functions
because compiler exports the functions without the @N
decoration
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tobivollebregt at gmail dot com
GCC build triplet: i486-linux-gnu
GCC host triplet: i486-linux-gnu
GCC target triplet: i586-mingw32msvc
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680
