"libtdclient.a: error adding symbols: file format not recognized" and "ld returned 1 exit status"

[Mazuh]

after #1241 (so there might be a few more evidences there, like the printed commands I used), I tried to run a few simple codes.

main.cpp:

#include <iostream>
#include <td/telegram/Client.h>
#include <td/telegram/td_api.h>
#include <td/telegram/td_api.hpp>

namespace td_api = td::td_api;

int main()
{
    td::Client::execute({0, td_api::make_object<td_api::setLogVerbosityLevel>(1)}); // if I remove this, everything works
    std::cout << "Hello World!" << std::endl;
    return 0;
}

(I tried to copy and paste the cpp example but the result is the same, any attempt to call the actual functions are bad, only the includes are working.)

and cmakelists.txt:

cmake_minimum_required(VERSION 3.10 FATAL_ERROR)

project("mysampleproject")

find_package(Td PATHS "../td/tdlib/" REQUIRED NO_DEFAULT_PATH)

add_executable("${PROJECT_NAME}" "src/main.cpp")

set_property(TARGET "${PROJECT_NAME}" PROPERTY CXX_STANDARD 14)

target_link_libraries("${PROJECT_NAME}" PRIVATE Td::TdStatic)
target_link_libraries("${PROJECT_NAME}" PRIVATE Td::TdJson)

then I get this error:

...
libtdclient.a: error adding symbols: file format not recognized

if I try to rebuild everything without Link Time Optimization:

...
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/mysampleproject.dir/build.make:96: mysampleproject] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/mysampleproject.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

I tried to compile using both master branch and v.1.6.0 tagged head, and erased build/ and tdlib/ before retrying.

---

does someone have any idea?

[levlam]

Do you have enough memory on the server for successful build?

[Mazuh]

yep, @levlam, there's more than enough, it's my own machine here, all good.

But I have more evidences!

Curiously, I switched the instructions to g++ instead of clang++ to buld tdlib and, tho memory consumption increased A LOT... my sample is now working.

here's what worked, to be specific:

export CXXFLAGS=""
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX:PATH=../tdlib -DTD_ENABLE_LTO=ON ..
cmake --build . --target install

[levlam]

g++ is known to need 2-2.5 times more memory than clang to build TDLib.

And the most common way to create a broken static library is to observe a compiler crash due to memory exhaustion.

[Mazuh]

But anyway, the g++ build is fine, even using more memory.

I think there's an issue with this clang++ instructions, then. Or it's just bad luck that it doesn't work for me, haha

[levlam]

libtdclient.a: error adding symbols: file format not recognized

This is expected with LTO, because when Link-Time optimization is used .a files contain parsed source code in a compiler-specifiс format to be used by linker instead of a compiled static library functions.

collect2: error: ld returned 1 exit status

This isn't expected without LTO, but it is impossible to find the reason without debugging the issue. One way to do that is to run

make VERBOSE=1

to find exactly invoked command and then retry it manually to investigate.

I managed to build TDLib on Ubuntu 20 using clang and build instructions from https://tdlib.github.io/td/build.html on a freshly installed Ubuntu 20 without any issues.