__imp___acrt_iob_func linking errors under msys2

[Jimmio92]

Hello,

I am trying to build racer from master branch (pulled yesterday) and it seems to be linking both the GNU C library like it should as well as MSVCRT.. and I'm not sure if that's where the problem lies. Basically, it seems this error occurs when a library is built with MSVC tools prior to VS2015 and then used in VS2015.. It also seems to pop up only in a few curl functions. Any ideas?

[kngwyu]

Hmm... It's upstream issue so I'm not sure I can handle it 😓
Now I updated cargo so could you please try to build once more?
But, in the long run, it seems to be better to use cargo metadata as subprocess 🙁

[Jimmio92]

Full build log: buildlog.txt

Nightly Rust. Master branch here. Msys2 up to date. GCC 8.2.0. Windows 10 x64 in a unix-like bash environment, basically.

[crlf0710]

@Jimmio92 This has been the case for quite a while now. It's because MSYS2 ships GCC 8.x, and Rust itself ships GCC 7.x. I have some experience dealing with this.

So basically you have two ways to workaround this issue.

1. Somehow get yourself an environment the same with those mingw-build files Rust ships, e.g. GCC 7.x etc.. (Hard)

2. a. remove rust-mingw component. (edit multirust-channel-manifest.toml to change rust-mingw from component to extensions, then rustup component remove rust-mingw).
   b. replace crt2.o and crt2dll.o with the ones from MINGW64/MINGW32 of MSYS2.
   c. build your crate.

This works until you do a rustup update then rust-mingw will be back, and you'll have to start over.

[Jimmio92]

crt2.o and crt2dll.o are no longer the name of the now multiple files named crtbegin and crtend, plus some mathematical section of the runtime. So.. I don't know what to do. I guess building Rust from source in this environment would alleviate this problem?

[crlf0710]

@Jimmio92 those files still exists. there was a typo however, it's called crt2dll.o dllcrt2.o . crtbegin and crtend files do exists, but they're unrelated.

They're located at(taking 64-bit example on my machine):

/mingw64/x86_64-w64-mingw32/lib/crt2.o
/mingw64/x86_64-w64-mingw32/lib/dllcrt2.o

And they come with mingw-w64-x86_64-crt-git 6.0.0.5193.a081b583-1 in MSYS2 package on my machine.

You should use them to replace (I'm using stable, but you might want to change the directory to nightly one):
<somewhere>\.rustup\toolchains\stable-x86_64-pc-windows-gnu\lib\rustlib\x86_64-pc-windows-gnu\lib\crt2.o

<somewhere>\.rustup\toolchains\stable-x86_64-pc-windows-gnu\lib\rustlib\x86_64-pc-windows-gnu\lib\dllcrt2.o

Also, be careful that since the gcc.exe will be removed as part of rust-mingw, any Rust program's compilation will be using the gcc.exe that comes from MSYS2 mingw64. It will error if it can't find it.

[kngwyu]

@Jimmio92
I think it's resolved in 2.1.5.
Could you try cargo +nightly install racer once more, please?

[mati865]

@crlf0710 in fact this is because Rust's GCC was build with way older mingw-w64 than MSYS2 (GCC version doesn't matter).