_pipe not available on UWP

[TheBlackOne]

Hey!

I am working in adding {fmt} to a project that compiles for UWP. Unfortunately, compiling for UWP fails:
C:\[omitted]\fmt\6.0.0\src\posix.cc(198): error C2039: '_pipe': is not a member of 'global namespace'

It would seem that _pipe is not available on UWP at all, and no workaround available: https://docs.microsoft.com/en-us/cpp/cppcx/crt-functions-not-supported-in-universal-windows-platform-apps?view=vs-2019

While I understand that UWP is not a popular platform to begin with, this is a showstopper on bringing the project I am working for forward in regards of string formatting and being proactive of preparing for C++20.

[TheBlackOne]

I believe the problem stems from here:

if (WIN32)
  check_symbol_exists(open io.h HAVE_OPEN)
...
if (HAVE_OPEN)
  add_headers(FMT_HEADERS posix.h)
  set(FMT_SOURCES ${FMT_SOURCES} src/posix.cc)

https://github.com/fmtlib/fmt/blob/master/CMakeLists.txt#L138
https://github.com/fmtlib/fmt/blob/master/CMakeLists.txt#L158

That check succeeds on UWP, as _open exists there. However, other CRT functions that are called in posix.cc do not (like the aforementioned _pipe), so the check for _open only does not embrace the whole situation.

[vitaut]

It's just a matter of adding another check similar to the one for open in CMake. Could you submit a PR since you in the best position to test it?

[vitaut]

Tentatively fixed in 9b7fe2a. If this doesn't help please submit a PR adjusting the UWP check in

fmt/include/fmt/posix.h

Line 34 in 9b7fe2a

(!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))

.

[TheBlackOne]

Ah sorry, I could not engage with this one sooner.
Thanks for looking into it, I really appreciate it.