rustc does not add the LIBPATH for ucrt.lib to the MSVC command line.

[briansmith]

When cargo build is used outside of an VS2015 {x86,x64} Native Tools Command Prompt, I receive this error during linking:

rustc: LINK : fatal error LNK1104: cannot open file 'ucrt.lib'

in librustc_trans/back/msvc/mod.rs:

    // The MSVC linker uses the LIB environment variable as the default lookup
    // path for libraries. This environment variable is normally set up by the
    // VS shells, so we only want to start adding our own pieces if it's not
    // set.
    //
    // If we're adding our own pieces, then we need to add two primary
    // directories to the default search path for the linker. The first is in
    // the VS install direcotry and the next is the Windows SDK directory.

When building using the VS2015 toolkit, there is a third path needed: The path to ucrt.lib. On my system, it is C:\Program Files (x86)\Windows Kits\10\lib\10.0.10150.0\ucrt\x64. Here is the full value of the LIB environment variable that vcvarsall.bat sets:

LIB=C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\LIB\amd64;C:\ProgramFiles (x86)\Microsoft Visual Studio 14.0\VC\ATLMFC\LIB\amd64;C:\Program Files (x86)\Windows Kits\10\lib\10.0.10150.0\ucrt\x64;C:\Program Files (x86)\Windows Kits\NETFXSDK\4.6\lib\um\x64;C:\Program Files (x86)\Windows Kits\8.1\lib\winv6.3\um\x64;

Here's the build output, reformatted so every parameter is on its own line:

error: linking with `link.exe` failed: exit code: 1104
note: "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC/bin\amd64\link.exe"
"/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC/lib\amd64"
"/LIBPATH:C:\Program Files (x86)\Windows Kits\8.1\Lib\winv6.3\um\x64"
"/NOLOGO"
"/NXCOMPAT"
"/LIBPATH:C:\Users\Example\AppData\Local\Apps\Rust-1.3\bin\rustlib\x86_64-pc-windows-msvc\lib"
"C:\Users\Example\Documents\p\ring\target\debug\build\ring-c7da49b4c8d6e8fe\build_script_build.0.o"
"/OUT:C:\Users\Example\Documents\p\ring\target\debug\build\ring-c7da49b4c8d6e8fe\build_script_build.exe"
"/OPT:REF,ICF"
"/DEBUG"
"/LIBPATH:C:\Users\Example\AppData\Local\Apps\Rust-1.3\bin\rustlib\x86_64-pc-windows-msvc\lib"
"std-74fa456f.lib"
"/LIBPATH:C:\Users\Example\Documents\p\ring\target\debug"
"/LIBPATH:C:\Users\Example\Documents\p\ring\target\debug\deps"
"/LIBPATH:C:\Users\Example\AppData\Local\Apps\Rust-1
.3\bin\rustlib\x86_64-pc-windows-msvc\lib"
"/LIBPATH:C:\Users\Example\Documents\p\ring\.rust\bin\x86_64-pc-windows-msvc"
"/LIBPATH:C:\Users\Example\Documents\p\ring\bin\x86_64-pc-windows-msvc"
"ws2_32.lib"
"userenv.lib"
"advapi32.lib"
"kernel32.lib"
"shell32.lib"
"msvcrt.lib"
"compiler-rt.lib"
note: LINK : fatal error LNK1104: cannot open file 'ucrt.lib'

[briansmith]

Also, here's the version information:

C:\Users\Example\Documents\p\rust [master]> rustc --version
rustc 1.3.0-nightly (cb4f102e3 2015-07-22)

C:\Users\Example\Documents\p\rust [master]> cargo --version
cargo 0.4.0-nightly (84ef25d 2015-07-23) (built 2015-07-23)

[alexcrichton]

Thanks for the report! Support for this was added in #27250 which I believe landed after the nightly you're using, so an update should fix it!