Precompiled headers don't work on windows with ninja & msvc

[kterhorst]

I tried the test case "common/13 pch" on windows with ninja & msvc and get the following error when I run ninja:

meson.py src build
...
cd build
ninja
[3/3] Linking target prog.exe
FAILED: cmd /c link /OUT:prog.exe prog.dir\prog.c.obj "/nologo"
prog.c.obj : error LNK2011: precompiled object not linked in; image may not run
prog.exe : fatal error LNK1120: 1 unresolved externals
ninja: build stopped: subcommand failed.

The problem can be fixed by manually adding the pch object file to the list of objects:

exe = executable('prog', 'prog.c',
c_pch : ['pch/prog_pch.c', 'pch/prog.h'],
objects : '../build/prog_pch.obj')

Meson should automatically add that file.

[jpakkane]

Which version of Visual Studio is this? Because the last time I tested this on VS2010 (the only version I have) it worked without needing to include the object file.

[jpakkane]

I checked and VS2010 definitely does not require that you link in the object file. It does not harm either, so I changed it to always add it in. Can you test whether current trunk works for you?

[kterhorst]

Yeah, it works for me now. The cpp pch sample which previously failed to compile also works now but I get the warning:

ninja
[1/3] Precompiling header ..\src\pch/prog_pch.cc
C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\xlocale(337) : wa
rning C4530: C++ exception handler used, but unwind semantics are not enabled. S
pecify /EHsc
[3/3] Linking target prog.exe

So I would suggest to add /EHsc by default.

By the way, meson generates the sanitycheck*.obj outside the build directory. It would be cleaner to put that file in the build directory or delete it.

[jpakkane]

Thanks for testing. I fixed the sanitycheck one just now.

As far as /EHsc goes, it seems to me that people might want to compile with different exception types so putting that in by default does not seem right (as you can't unset the core flags set by Meson). Adding this in by yourself is a one-liner (or three lines if you want to wrap it in an if clause):

add_global_arguments('/EHsc', language : 'cpp')

I'm closing this issue as fixed now. If you have more to say about the exception argument, please open a new issue.

Thanks,