Re: [boost] WCHAR_MAX not defined on openbsd

Subject: Re: [boost] WCHAR_MAX not defined on openbsd
From: Bo Persson (bop_at_[hidden])
Date: 2010-08-16 13:17:35

Kim Barrett wrote:
> 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".
>

It is wrong for C++0x, which specifically mentions that the macros are 
NOT to be used in <cstdint>.
§18.4.1

Bo Persson