wine: missing path to MinGW's libstdc++

[mojca (Mojca Miklavec)]

If users try to cross-compile binaries for Windows using MinGW-w64, they cannot run those binaries using Wine unless the binaries are compiled statically. On some IRC channel developers suggested:

Wine requires that the path be set in its own conf file (not PATH envvar) that points to wherever the c++ standard library is. At least on Linux.

and

you need something like wine reg add HKCU\\Environment /v PATH /d "z:\\usr\\$PRE\\bin;z:\\usr\\local\\$PRE\\bin" /f with PRE=i686-w64-mingw32 or similar

The relevant files are at:

  /opt/local/i686-w64-mingw32/lib/libatomic-1.dll
  /opt/local/i686-w64-mingw32/lib/libgcc_s_sjlj-1.dll
  /opt/local/i686-w64-mingw32/lib/libgfortran-4.dll
  /opt/local/i686-w64-mingw32/lib/libobjc-4.dll
  /opt/local/i686-w64-mingw32/lib/libquadmath-0.dll
  /opt/local/i686-w64-mingw32/lib/libssp-0.dll
  /opt/local/i686-w64-mingw32/lib/libstdc++-6.dll

as well as under x86_64-w64-mingw32, but I could not make 64-bit binaries work with our Wine anyway, so probably only the 32-bit is relevant.

Steps to reproduce:

$ cat hello.cpp 
#include <iostream>
int main()
{
	std::cout << "Hello world\n";
	return 0;
}

$ sudo port install i686-w64-mingw32-gcc

$ i686-w64-mingw32-g++ hello.cpp -o hello.exe

$ wine hello.exe 
err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\tmpj\\hello.exe") not found
err:module:LdrInitializeThunk Main exe initialization for L"Z:\\tmp\\hello.exe" failed, status c0000135

[ryandesign (Ryan Carsten Schmidt)]

Sorry, I don't know what to do with this. If someone else does, please feel free to fix the affected ports.

[raimue (Rainer Müller)]

The mentioned registry key would be part of the wine prefix you are using. Even if the default PATH was changed, it would only affect new prefixes and do nothing for existing wine prefixes.

Do other Linux distributions really somehow set this by default? For reference, there are similar instructions for ​Fedora and ​Gentoo, which appear to be similar to the wine reg add shown above and are required to be carried out by the user.

You could also experiment with DLL overrides via winecfg or ​WINEDLLOVERRIDES.

The easiest workaround is probably to just copy (or symlink?) the required DLLs right next to the .exe and they should be found.

[mojca (Mojca Miklavec)]

I believe it would be sufficient to provide clear notes, like for Retina display (which was very useful, even though a bit confusing and a number of other settings like font sizes were needed as well, so it would help to have a more extensive wiki entry somewhere anyway). At the moment the user doesn't even know what to do.

I'm also a bit worried that our paths are wrong. Both instructions have PATH which ends with bin rather than lib. I wonder whether I used some wrong flags for building the gcc cross-compiler.

[mojca (Mojca Miklavec)]

I addressed this in ​https://github.com/macports/macports-ports/pull/1048:

  If you want your MinGW-generated windows binaries to work under wine out-of-the-box
  (and they are not statically linked), you can instruct wine
  to automatically search for dll-s by running:
      wine regedit
  Nagivate to:
      [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment]
  or
      [HKEY_CURRENT_USER\Environment]
  and add
      Z:\opt\local\i686-w64-mingw32\bin
  to the 'PATH' variable.

I hope the text is OK. One could use wine reg add, but I don't want infinitely long notes.

Suggestions welcome.

[mojca (Mojca Miklavec)]

Replying to raimue:

The easiest workaround is probably to just copy (or symlink?) the required DLLs right next to the .exe and they should be found.

The easiest workaround is to build the binaries statically with

-static-libgcc -static-libstdc++

I didn't find a way to achieve the same with libpthreads though.

Copying gets super annoying when running CMake or Meson with test cases. I don't want to worry about copying all the libraries to all the places where unit tests live.

Since most Wine users are unlikely to ever compile anything for windows under Mac, it makes more sense to add those notes to the cross-compiler than to wine. I only added them to i686 because we don't have support for 64-bit Windows yet.

[mojca (Mojca Miklavec)]

In b01bc691925621c47decdc620ca7c18da142f89c/macports-ports:

i686-w64-mingw32-gcc: add notes for wine users

Closes: #55273