[cfe-dev] Extra #defines for Windows SDK 6.0a/VS2008

[Bjorn Reese]

On 2010-08-06 15:45, David Chisnall wrote:
> On 6 Aug 2010, at 14:21, Douglas Gregor wrote:
>
>> I wonder how much will break if we start defining _MSC_VER? Does anyone know how mingw deals with this?
>
> We already define the GCC version macros so that we can act as a drop-in replacement for GCC.  If we're aiming to act as a drop-in replacement for MSVC then it would make sense to define their version macros and treat any incompatibilities in MS-extensions mode as bugs, just as we treat incompatibilities with GCC in GNU C modes as bugs.

Defining _MSC_VER or __GNUC__ or any other macro that identifies another
compiler is a problem because it makes it very difficult to handle
differences or defects via predefined macros.

Many projects rely on this, e.g. boost, wxwidget, and indeed your own
libcxx.