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mirage / irmin-watcher

Portable implementation of the Irmin Watch API
ISC License
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Use _WIN32 and MAX_PATH on Windows #34

Closed jonahbeckford closed 2 years ago

jonahbeckford commented 2 years ago

This PR does two changes:

  1. As in other mirage packages, changed WIN32 macro to _WIN32 (more below)
  2. Use MAX_PATH for MSVC compiler to fill-in for missing PATH_MAX

According to https://reviews.llvm.org/D40285 the _WIN32 macro works across MSVC, GCC and clang compilers:

In MSVC, WIN32 and WIN64 are never defined by the compiler, neither by system headers. Project files created by the IDE often contains them set manually though.

GCC on the other hand predefines both _WIN32 and WIN32 (and similarly for -64), but only when using the GNU standards additions (which are enabled by default) x86_64-w64-mingw32-gcc -E -dM - < /dev/null | grep WIN32 does include both, while the unprefixed one vanishes if you add e.g. -std=c99 (but are still included if you set -std=gnu99).

clang on the other hand doesn't check the standards version, but provides both WIN32 and _WIN32. And for the really inconsistent case, with clang -target x86_64-w64-mingw32 -E -dM - < /dev/null, you will have WIN64, _WIN64 and _WIN32, but no unprefixed WIN32.

So WIN32 is incorrect, even on GCC compilers.

The _WIN32 macro is documented at https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-170

samoht commented 2 years ago

Thansk!