Is it possible to use eCAL with Windows+MinGW g++?

[CyFio]

Problem Description

I am attempting to use eCAL to solve the inter-process communication between an application built under minGW and another built with MSVC. When integrating eCAL with MSVC app, it works fine, however, I get link errors when using minGW.

Details

here is the tools I use for integration

• IDE: Eclipse IDE
• Compiler: MinGW64 g++(gcc version 10.3.0 (Rev2, Built by MSYS2 project)
• eCAL version 5.12.0 (windows install ver, with c++/py example tested)

Steps

here is the compile command for a simple c++ project

//src/simpleC.cpp
#include <iostream>
using namespace std;
#include <ecal/ecal.h>

int main(int argc, char**argv) {
    eCAL::Initialize(argc, argv, "Hello World Publisher");
	cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
	eCAL::Finalize();
	return 0;
}

g++ "-IG:\\Programs\\eCAL\\include" -O0 -g3 -Wall -c -fmessage-length=0 -o "src\\simpleC.o" "..\\src\\simpleC.cpp" 
g++ "-LG:\\Programs\\eCAL\\lib" -o simpleC.exe "src\\simpleC.o" "-lG:\\Programs\\eCAL\\lib\\ecal_core.lib"  # G:\Programs\eCAL is the eCAL install path

both IDE's intellisense and g++ successfully finds the include headers. However, I get link error message as below

win64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lG:\Programs\eCAL\lib\ecal_core.lib

Attempted Solutions

I am not familiar with mingw gcc. Maybe I have to recompile eCAL with mingw gcc? But I cant find any instructions on MinGW compilation. Also, I am not sure if two eCALs(msvc&minGW gcc) can work together.

[FlorianReimold]

Hi @CyFio

Our official binary SDK for Windows is built with Visual Studio 2019 (since eCAL 5.12, it was Visual Studio 2015 before). So yes, you will have to compile eCAL with MinGW yourself, if you want to use that compiler for linking.
We don't support MinGW though and I think nobody has tried to compile eCAL with MinGW for years. So it is likely that you will run into some issues. You can try to follow the Linux build instructions, but you will have to take care of the build dependencies yourself, as those come from apt-get on Linux.

If you want to try it, I recommend using a very minimal eCAL setup, that only consists of the eCAL Core.

Here is a set of CMake options for you to start:

        -DHAS_HDF5=OFF \
        -DHAS_QT5=OFF \
        -DHAS_CURL=OFF \
        -DHAS_CAPNPROTO=OFF \
        -DHAS_FTXUI=OFF \
        -DBUILD_DOCS=OFF \
        -DBUILD_APPS=OFF \
        -DBUILD_SAMPLES=OFF \
        -DBUILD_TIME=OFF \
        -DBUILD_PY_BINDING=OFF \
        -DBUILD_STANDALONE_PY_WHEEL=OFF \
        -DBUILD_CSHARP_BINDING=OFF \
        -DBUILD_ECAL_TESTS=OFF \
        -DECAL_INCLUDE_PY_SAMPLES=OFF \
        -DECAL_INSTALL_SAMPLE_SOURCES=OFF \
        -DECAL_JOIN_MULTICAST_TWICE=OFF \
        -DECAL_NPCAP_SUPPORT=OFF \
        -DECAL_THIRDPARTY_BUILD_CMAKE_FUNCTIONS=ON \
        -DECAL_THIRDPARTY_BUILD_PROTOBUF=OFF \
        -DECAL_THIRDPARTY_BUILD_SPDLOG=ON \
        -DECAL_THIRDPARTY_BUILD_TINYXML2=OFF \
        -DECAL_THIRDPARTY_BUILD_FINEFTP=OFF \
        -DECAL_THIRDPARTY_BUILD_CURL=OFF \
        -DECAL_THIRDPARTY_BUILD_GTEST=OFF \
        -DECAL_THIRDPARTY_BUILD_HDF5=OFF \
        -DECAL_THIRDPARTY_BUILD_RECYCLE=OFF \
        -DECAL_THIRDPARTY_BUILD_TCP_PUBSUB=ON \
        -DECAL_THIRDPARTY_BUILD_QWT=OFF \
        -DECAL_THIRDPARTY_BUILD_YAML-CPP=OFF \
        -DCMAKE_BUILD_TYPE=Release

[CyFio]

Well, that ld error may result from missing env vars or cache created by unsuccessful configs before.. I finally get rid of it after deleting the build folder, checking env vars and rebuilding all. HOWEVER, here is the error I got when it is nearly done. (rec addon passed)

[ 97%] Building CXX object ecal/core/CMakeFiles/core.dir/src/sys_usage.cpp.obj
[ 98%] Building CXX object ecal/core/CMakeFiles/core.dir/src/ecal_timer.cpp.obj
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp: In function 'int eCAL_Monitoring_PubMonitoring(int, const char*)':
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:414:30: warning: 'int eCAL::Monitoring::PubMonitoring(bool, std::string)' is deprecated: use GetMonitoring and publish yourself [-Wdeprecated-declarations]
 414 |     return(eCAL::Monitoring::PubMonitoring(state_ != 0, name_));
     |                              ^~~~~~~~~~~~~
In file included from E:/.../eclipse/ecal/ecal/core/include/ecal/ecal.h:37,
                from E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:26:
E:/.../eclipse/ecal/ecal/core/include/ecal/ecal_monitoring.h:111:18: note: declared here
 111 |     ECAL_API int PubMonitoring(bool state_, std::string name_ = "ecal.monitoring");
     |                  ^~~~~~~~~~~~~
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:414:62: warning: 'int eCAL::Monitoring::PubMonitoring(bool, std::string)' is deprecated: use GetMonitoring and publish yourself [-Wdeprecated-declarations]
 414 |     return(eCAL::Monitoring::PubMonitoring(state_ != 0, name_));
     |                                                              ^
In file included from E:/.../eclipse/ecal/ecal/core/include/ecal/ecal.h:37,
                from E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:26:
E:/.../eclipse/ecal/ecal/core/include/ecal/ecal_monitoring.h:111:18: note: declared here
 111 |     ECAL_API int PubMonitoring(bool state_, std::string name_ = "ecal.monitoring");
     |                  ^~~~~~~~~~~~~
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp: In function 'int eCAL_Monitoring_PubLogging(int, const char*)':
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:419:30: warning: 'int eCAL::Monitoring::PubLogging(bool, std::string)' is deprecated: use GetLogging and publish yourself [-Wdeprecated-declarations]
 419 |     return(eCAL::Monitoring::PubLogging(state_ != 0, name_));
     |                              ^~~~~~~~~~
In file included from E:/.../eclipse/ecal/ecal/core/include/ecal/ecal.h:37,
                from E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:26:
E:/.../eclipse/ecal/ecal/core/include/ecal/ecal_monitoring.h:122:18: note: declared here
 122 |     ECAL_API int PubLogging(bool state_, std::string name_ = "ecal.logging");
     |                  ^~~~~~~~~~
E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:419:59: warning: 'int eCAL::Monitoring::PubLogging(bool, std::string)' is deprecated: use GetLogging and publish yourself [-Wdeprecated-declarations]
 419 |     return(eCAL::Monitoring::PubLogging(state_ != 0, name_));
     |                                                           ^
In file included from E:/.../eclipse/ecal/ecal/core/include/ecal/ecal.h:37,
                from E:\...\eclipse\ecal\ecal\core\src\ecalc.cpp:26:
E:/.../eclipse/ecal/ecal/core/include/ecal/ecal_monitoring.h:122:18: note: declared here
 122 |     ECAL_API int PubLogging(bool state_, std::string name_ = "ecal.logging");
     |                  ^~~~~~~~~~
[100%] Linking CXX shared library ..\..\bin\libecal_core.dll
E:/.../.../mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: CMakeFiles\core.dir/objects.a(ecal_config_reader.cpp.obj):ecal_config_reader.cpp:(.text+0xce5): undefined reference to `__imp__wdupenv_s'
E:/.../.../mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: CMakeFiles\core.dir/objects.a(ecal_config_reader.cpp.obj):ecal_config_reader.cpp:(.text+0x22b3): undefined reference to `__imp__wdupenv_s'
E:/.../.../mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: CMakeFiles\core.dir/objects.a(ecal_timegate.cpp.obj):ecal_timegate.cpp:(.text+0x963): undefined reference to `__imp__wdupenv_s'
collect2.exe: error: ld returned 1 exit status
ecal\core\CMakeFiles\core.dir\build.make:1209: recipe for target 'bin/libecal_core.dll' failed
mingw32-make.exe[2]: *** [bin/libecal_core.dll] Error 1
CMakeFiles\Makefile2:878: recipe for target 'ecal/core/CMakeFiles/core.dir/all' failed
mingw32-make.exe[1]: *** [ecal/core/CMakeFiles/core.dir/all] Error 2
Makefile:154: recipe for target 'all' failed
mingw32-make.exe: *** [all] Error 2

[FlorianReimold]

A stackoverflow article explains that those functions have been added with Visual Studio 2008, but didn't make it in the default msvcrt which mingw is using. However, there seems to be a way to let the MSYS2 toolchain link the Visual Studio libraries instead, which should in theory fix the issue. Here is the link to Stackoverflow:

https://stackoverflow.com/questions/61553637/which-lib-do-i-have-to-link-for-wdupenv-s

Btw: The function is used for querying environment Variables:

ecal/ecal/core/src/util/getenvvar.h

Line 38 in 210d236

errno_t err = _wdupenv_s(&val, &len, EcalUtils::StrConvert::Utf8ToWide(key).c_str());

[CyFio]

I solved the wdupenv link error by adding following lines to ecal/core/CMakeLists.txt

# add link flags to msys2
execute_process(COMMAND uname OUTPUT_VARIABLE uname)
if (uname MATCHES "^MSYS" OR uname MATCHES "^MINGW")
    message("This is MSYS")
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ")
    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}  -mcrtdll=msvcr120  -lversion")
    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}  -mcrtdll=msvcr120  -lversion")
    set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} -mcrtdll=msvcr120  -lversion")
else()
    message("This is not MSYS")
endif()

currently there is still an error with ecal.rc:

I dont know what does that module do, I thought it is about shared library but I currently only needs static link, so I just comment out the lines in CMakeLists that include the ecal.rc:

ecal/ecal/core/CMakeLists.txt

Lines 307 to 312 in 5bc279f

	if(WIN32)
	set(ecal_c_win_src
	src/win32/dll/dllmain.cpp
	src/win32/dll/ecal.rc
	)
	endif()

then it works:

Here is what I got:

It look quite different from what I got from installation, how should I test it?

Btw, the CPack phase is not successful, though

[FlorianReimold]

Awesome that you got it working! 👍👍👍

The .rc and dllmain file is probably too MSVC specific. I gues, gcc organizes things differently, even when being used on Windows. So maybe we should replace if (WIN32) by if (MSVC).

It look quite different from what I got from installation, how should I test it?

I think you are ready to link your msys app against your compiles eCAL! I wouldn't worry obout it looking differently than what you get from the binary installation. I mean, you completely changed the compiler and disabled pretty much all components except the eCAL Core. So it is expected to look differently.

So I guess you should try to compile your app with a CMAKE_PREFIX_PATH pointing to your custom compiled eCAL.

Btw, the CPack phase is not successful, though

Hm, not sure what the issue is there. But I think you can just install it in a local directory with cmake and go from there. Your CPack complains about udpcap, which is strange as you didn't build that (and probably cannot build it with MSYS2)

[CyFio]

I tried it in the project I want to integrate and it works as expected. Thanks for help!😄

It shows an error that 'Could not load eCAL time sync module ecaltime-localtime.dll', but recv python script can catch the sent messages. Is there anything that should be done for that warning?