format.cc (in header only mode) includes windows.h without defining WIN32_LEAN_AND_MEAN

[gabime]

and this for example breaks boost and other libs

[vitaut]

I don't think it's a good idea to define WIN32_LEAN_AND_MEAN there because it may break users who include windows.h without this macro and use these rare features. There are two alternative solutions:

1. Define FMT_USE_WINDOWS_H to 0 if you don't need Windows error reporting functionality and Unicode converters provided by C++ Format.
2. Define WIN32_LEAN_AND_MEAN yourself if you are OK with potential issues.

This can be done in the same place where you define FMT_HEADER_ONLY.

[gabime]

In this case I might define FMT_USE_WINDOWS_H to 0 in spdlog..

What is the Windows error reporting functionality?

[vitaut]

It's WindowsError exception and report_windows_error function that automatically translate the error code returned by GetLastError() into a text message. The formatting functions don't use this, so if you don't use this either, spdlog won't be affected.