Zig: Zig c++ fails to link against certain static library functions

[0syf3r]

Version:
zig-linux-x86_64-0.6.0+2c882b2e6

test.cpp:

#include <iostream>
#include "OgreStringConverter.h"
#include "OgreString.h"

int main() {
    float x = 1.1;
    Ogre::String s = Ogre::StringConverter::toString(x);
    std::cout << s << std::endl;
    return 0;
    }

Command:
zig c++ -o test test.cpp -I ogre/Ogre/ogre-next/build/sdk/include/OGRE/ -D_DEBUG -Logre/Ogre/ogre-next/build/sdk/lib/ -lOgreMainStatic_d -lpthread

Output:

...
Compile C Objects [1/1] test.cpp...lld: error: undefined symbol: Ogre::StringConverter::toString(float, unsigned short, unsigned short, char, unsigned int)
>>> referenced by test.cpp
>>>               zig-cache/o/LI0cI4b1ucy8of90Qy6RkfJ7DJ4oDekve4vs2lrmT3SqgXqgxRzBv10l9TyuY7fY/test.o:(main)

Ogre is a 3d rendering library.
I can confirm that both clang++ and g++ can successfully compile and link this executable with the exact same arguments. The interesting part is that if I don't use Ogre::StringConverter::toString, then Zig can still link and use Ogre::String with no problem, so only certain functions of the static library are failing to link.

[FireFox317]

Please first test the issue on the master branch of Zig before submitting an issue. You can download a master binary at ziglang.org/download

[0syf3r]

Exact same error with today's build(zig-linux-x86_64-0.6.0+2c882b2e6).

[0syf3r]

I think I have a reproducible example now:

OgreStringConverter.h:

#ifndef __StringConverter_H__
#define __StringConverter_H__

#include <ios> // for fmtflags
#include <string>

namespace Ogre {
    class StringConverter
    {
    public:
        /** Converts a float to a String. */
        static std::string toString(float val, unsigned short precision = 6,
                               unsigned short width = 0, char fill = ' ',
                               std::ios::fmtflags flags = std::ios::fmtflags(0));
    };
}
#endif

OgreStringConverter.cpp:

#include "OgreStringConverter.h"
#include <sstream>

namespace Ogre {
    std::string StringConverter::toString(float val, unsigned short precision,
                                     unsigned short width, char fill, std::ios::fmtflags flags)
    {
        return "foo";
    }

}

Link into static library:
$ clang++ -c OgreStringConverter.cpp
$ ar rvs libogre.a OgreStringConverter.o

Create test:
test.cpp:

#include <iostream>
#include "OgreStringConverter.h"
#include <string>

int main() {
    float x = 1.1;
    std::string s = Ogre::StringConverter::toString(x);
    std::cout << s << std::endl;
    return 0;
    }

Confirm that it works with clang++:

$ clang++ -o test test.cpp -L. -logre
$ ./test 
foo

Replace clang++ with zig c++ and you get this:

 $ ../zig-linux-x86_64-0.6.0+2c882b2e6/zig c++ -o test test.cpp -L. -logre
lld:error: undefined symbol: Ogre::StringConverter::toString(float, unsigned short, unsigned short, char, unsigned int)
>>> referenced by test.cpp
>>>               zig-cache/o/Nwbrj1nXWa9XTa12FakBpMtbQSj119lJKVLiI-M6HMk8q-5IC1eJctCrijgBlSPG/test.o:(main)

[0syf3r]

Oh, and on Windows, I can't even get past the compiler:

zig: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
Compile C Objects [1/1] test.cpp...zig: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
zig: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
Build Dependencies...c++abi [2] Compile C Objects [1/19] abort_message.cpp...zig: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
zig: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
In file included from D:\zig-is-broken\zig-windows-x86_64-0.6.0+2c882b2e6\lib\zig\libcxxabi\src/cxa_aux_runtime.cpp:14:
In file included from D:\zig-is-broken\zig-windows-x86_64-0.6.0+2c882b2e6\lib\zig\libcxx\include\typeinfo:72:
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.25.28610\include\vcruntime_typeinfo.h:119:13: error: target of using declaration conflicts with declaration already in scope
    using ::type_info;
            ^
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.25.28610\include\vcruntime_typeinfo.h:69:7: note: target of using declaration
class type_info
      ^
D:\zig-is-broken\zig-windows-x86_64-0.6.0+2c882b2e6\lib\zig\libcxxabi\include\cxxabi.h:29:27: note: conflicting declaration
class _LIBCXXABI_TYPE_VIS type_info; // forward declaration
                          ^
1 error generated.

[wozeparrot]

Your example works for me on linux with zig master, but the example you showed is wrong? The example should print foo should it not?

[wozeparrot]

Ok it seems that when the static library is compiled with clang or gcc, then you try to link to it with zig, it breaks.

[0syf3r]

@wozeparrot My bad: I was posting the output from an older version of the test. I updated the output so people don't get confused.

[wozeparrot]

It seems to be caused by zig c++ not handling [abi:cxx11] function names that are generated by clang and gcc