Re: Static compilation and use in a DLL compatible with rundll32

Hi again,

Well I figured it out.
The library was trying to load pthread on the Windows environment
where obviously didn't exist.
The following flags were used to avoid this circumstance.
--enable-threaded-resolver --disable-pthreads

Regards

El mié., 6 may. 2020 a las 15:51, Phoenix . (<phoenixdev22_at_gmail.com>) escribió:
>
> Hello,
>
> First message for this mailist, many thanks for your help and time guys.
>
> I am trying to crosscompile an statically version of libcurl which can
> be use by mingw to create a DLL usable by rundll32 on a Windows
> system.
> I am trying this from an Ubuntu 18.04.4 LTS with the current git
> version of libcurl which is 7.70.1-DEV and I am executing the library
> with: rundll32.exe "<PathToDLL>",AltEntry
> I also verified that the exported function is present through a small
> windows tool called dllexp.exe.
>
> Unfortunately, when including the libcurl.a library in the compilation
> process, the library stops being loaded by rundll32.
> After having a look with a debugger, I realized that the DLL its
> unloaded after tried to be loaded. Last DLL which tries to load is
> ws2_32.dll but at this point I am not really sure if it just something
> problematic with it in my compilation process or it is just the last
> dependency libcurl is trying to load.
>
> This is the error I receive.
> ---------------------------
> RunDLL
> ---------------------------
> There was a problem starting libtest.dll
> The specified module could not be found.
> ---------------------------
> OK
> ---------------------------
>
> Which makes sense since it's been unloaded from memory. But why?
>
> I tried tons of different configurations but for the sake of
> simplicity I configured a separately project and used the following:
> ./configure \
> --prefix=`pwd`/build \
> --host=x86_64-w64-mingw32 \
> --disable-shared \
> --disable-ldap \
> --disable-ldaps
>
> make -j`nproc`
> make install
>
> ------------------- CMakeLists.txt -------------------
> cmake_minimum_required(VERSION 3.16)
> project(test C)
>
> set(CMAKE_C_STANDARD 99)
> set(CMAKE_VERBOSE_MAKEFILE on)
>
> include_directories(extra/curl/include)
> link_directories(extra/curl/lib)
>
> add_definitions(-DCURL_STATICLIB -DWINDOWS)
> add_library(
> test SHARED
> library.c library.h
> )
>
> target_compile_options(test PRIVATE -Wall)
> target_link_libraries(test curl pthread ws2_32)
>
> --------------- mingw-w64-x86_64.cmake ---------------
> set(CMAKE_SYSTEM_NAME Windows)
> set(TOOLCHAIN_PREFIX x86_64-w64-mingw32)
>
> set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}-gcc)
> set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}-g++)
> set(CMAKE_Fortran_COMPILER ${TOOLCHAIN_PREFIX}-gfortran)
> set(CMAKE_RC_COMPILER ${TOOLCHAIN_PREFIX}-windres)
>
> set(CMAKE_FIND_ROOT_PATH /usr/${TOOLCHAIN_PREFIX})
>
> set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
> set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
> set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
>
> set(CMAKE_FIND_LIBRARY_PREFIXES "lib" "")
> set(CMAKE_FIND_LIBRARY_SUFFIXES ".dll" ".dll.a" ".lib" ".a")
>
> ------------------------------------------------------
>
> The source code is just a DLLMain entry point + DLLExport function
> which call MessageBox an curl_easy_init() to verify everything worked
> and that I can build above it. I don't think it would be necessary but
> I could include those source files too.
>
> My IDE is CLion and I am compiling the project by specifying in the
> cmake section of the project settings
> -DCMAKE_TOOLCHAIN_FILE=./mingw-w64-x86_64.cmake.
> Since the CMakeLists.txt is set to verbose I can see a lot of output
> staying that everything is correct. I guess the most valuable string
> is the following mingw32 compilation command.
> /usr/bin/x86_64-w64-mingw32-gcc -DCURL_STATICLIB -DWINDOWS
> -Dtest_EXPORTS @CMakeFiles/test.dir/includes_C.rsp -g -Wall
> -std=gnu99 -o CMakeFiles/test.dir/library.c.obj -c
> /home/diego/CLionProjects/test/library.c
>
> I also checked the options used by the compilation process via
> curl-config and they seem fine to me.
> $ ./curl-config --built-shared --cc --cflags --features --static-libs
> no
> x86_64-w64-mingw32-gcc
> -DCURL_STATICLIB -I/[snipped]/curl/build/include
> IPv6
> AsynchDNS
> /[snipped]/curl/build/lib/libcurl.a -lws2_32
>
> ------------------------------------------------------
>
> Could you please point me what I am doing wrong here? Probably is
> something I messed up since I am not used to cross compilations
> processes.
>
>
> Many thanks for your help,
> Cheers

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Received on 2020-05-08