MSVC ARM64 build error.

[wyattoday]

When compiling the static libraries for ARM64 with vs2019, the build fails with the following error:

compile-c-c++ bin.v2\libs\thread\build\msvc-14.2\release\address-model-64\architecture-arm\link-static\runtime-link-static\threadapi-win32\threading-multi\win32\tss_pe.obj
tss_pe.cpp
libs\thread\src\win32\tss_pe.cpp(104): fatal error C1189: #error:  Unsupported platform

    call "bin.v2\standalone\msvc\msvc-14.2\address-model-64\architecture-arm\msvc-setup.bat"  >nul
 cl /Zm800 -nologo @"bin.v2\libs\thread\build\msvc-14.2\release\address-model-64\architecture-arm\link-static\runtime-link-static\threadapi-win32\threading-multi\win32\tss_pe.obj.rsp"

...failed compile-c-c++ bin.v2\libs\thread\build\msvc-14.2\release\address-model-64\architecture-arm\link-static\runtime-link-static\threadapi-win32\threading-multi\win32\tss_pe.obj...

The fix is rather simple (it's a missing define). In src/win32/tss_pe.cpp, on line 101, change this:

#elif defined (_M_X64) || defined (_M_ARM)

To this:

#elif defined (_M_X64) || defined (_M_ARM) || defined (_M_ARM64)

So, that full #if-def block will look like this:

#if defined (_M_IX86)
#pragma comment(linker, "/alternatename:__pRawDllMainOrig=__pDefaultRawDllMainOrig")
#elif defined (_M_X64) || defined (_M_ARM) || defined (_M_ARM64)
#pragma comment(linker, "/alternatename:_pRawDllMainOrig=_pDefaultRawDllMainOrig")
#else  /* unknown Windows target (not x86, x64, ARM, ARM64) */
#error Unsupported platform
#endif  /* defined (_M_X64) || defined (_M_ARM) || defined (_M_ARM64) */

If you want I can make this is a pull request, but this is a simple enough change I figured one of the maintainers could make the 1-liner change.

[viboes]

Hi, thanks for the report.

I would prefer a PR. Is this something you could do?

[wyattoday]

Sure, here's the fix: https://github.com/boostorg/thread/pull/282

[wyattoday]

Perfect, thanks!