On Aug 15, 2010, at 12:09 PM, John Maddock wrote:
hi there, i'm using openbsd 4.7 with g++ 4.2.4 installed from openbsd packages. i've tried building both boost 1.43 and 1.44rc, and both have several libraries fail due to WCHAR_MAX not being defined. this appears to be because __STDC_LIMIT_MACROS is not defined while processing /usr/include/stdint.h. i built boost with ./bjam cxxflags='-D__STDC_LIMIT_MACROS' and there are no more errors about WCHAR_MAX not being defined. perhaps this define should be added to boost/cstdint.hpp, or is there a deeper reason why WCHAR_MAX is not being defined correctly?
The std doesn't specify that some magic macro has to be defined before WCHAR_MAX gets defined
The C++ standard doesn't, but the C99 standard does! See footnote in 7.18.2 Limits of specified-width integer types. This is one of several places where C99 added features to C89 and notes that "C++ implementations should define these macros only when ..." some specified macro is defined before the relevant header is included.
- in any case by the time a boost header is #included it's too late to define such a macro because the system header may have already been #included by the program.
Which of course makes that C99-specified behavior a real pain to deal with. And of course that specified behavior is probably quite wrong for C++0x, but the C99 standard doesn't mention the scope of that behavior. And to add to the confusion, it is worded as a "should" rather than a "shall".