various error compiling for RPI B+ (SOLVED)

[edefranco]

Hi, I try to install rpos on a RPI B+ with wheezy, gcc updated to 4.9.2, cmake 3.0.2 and kernel 4.1.19+, npm 8.4.0 and have some compiling problems with v4l2rtspserver 1) /root/rpos/v4l2rtspserver/main.cpp: In function ‘std::string getV4l2Alsa(const string&)’: /root/rpos/v4l2rtspserver/main.cpp:157:58: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 deviceid = std::string(std::istreambuf_iterator{ifsd}, {});

Resolved changing in CMakeList.txt the row: set(CMAKE_CXX_STANDARD 11)

into

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

2) -- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) -- Configuring done CMake Error at CMakeLists.txt:25 (add_executable): Target "v4l2rtspserver" links to target "Threads::Threads" but the target was not found. Perhaps a find_package() call is missing for an IMPORTED target, or an ALIAS target is missing?

Resolved installing pkg-config and (but I am not sure that this modify is really correct) changing in CMakeList.txt this:

find_package (Threads) target_link_libraries (${PROJECT_NAME} Threads::Threads)

to

find_package (Threads) target_link_libraries (${PROJECT_NAME})

if (TARGET Threads::Threads) target_link_libraries (${PROJECT_NAME} Threads::Threads) endif()

3) NOT RESOLVED ! Linking CXX executable v4l2rtspserver /usr/bin/ld: liblibv4l2rtspserver.a(DeviceSource.cpp.o): undefined reference to symbol 'pthread_join@@GLIBC_2.4' //lib/arm-linux-gnueabihf/libpthread.so.0: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status CMakeFiles/v4l2rtspserver.dir/build.make:89: set di istruzioni per l'obiettivo "v4l2rtspserver" non riuscito make[2]: [v4l2rtspserver] Errore 1 CMakeFiles/Makefile2:96: set di istruzioni per l'obiettivo "CMakeFiles/v4l2rtspserver.dir/all" non riuscito make[1]: [CMakeFiles/v4l2rtspserver.dir/all] Errore 2 Makefile:147: set di istruzioni per l'obiettivo "all" non riuscito make: *** [all] Errore 2

Looking here for similar problem: microsoft/cpprestsdk#927

I think I understand that the problem maybe is correlated to the linking order of pthreads ... but I am no sure also about my previous modified to CMakeList.txt about Thread ...

Any help is greatly appreciated

Emilio

[mpromonet]

Hi Emilio,

It is probably simpler to cross compile, or using docker or snap ? About thread you may try -pthread

Best Regards, Michel.

[edefranco]

I Michel, thank for your answer. No, I am compiling directly on RPI, no docker, no snap. I download from git and give cmake . && make. Where I can put -pthread as you suggested ?

Emilio

[mpromonet]

Hi Emilio,

In CFLAGS & LDFLAGS this is what I guess makes the abstraction Threads.

Best Regards, Michel.

[edefranco]

Hi Michel,

I modified again the CMakeList.txt as:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pthread")

and the pthread section now is:

set(CMAKE_THREAD_PREFER_PTHREAD TRUE) set(THREADS_PREFER_PTHREAD_FLAG TRUE) find_package (Threads)

target_link_libraries (${PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})

if (TARGET Threads::Threads) target_link_libraries (${PROJECT_NAME} Threads::Threads) endif()

and (but I don't know if this is important) I have moved the ptheard after librtsp.

The compilation ending whitout error ! VERY GOOD!

I write this notes in the eventuality that some one encounter my same problem.

Thank again, know staring the testing (I hope all working fine)

Emilio