Darren Garvey-3 wrote:
This might not be a "pure" Boost question but do you know if compilers portably support the 'not' keyword?
int main ( ) { if(not false) return 0; return 1; }
This compiles on GCC but not on MSVC... Why? If you look at the C++ standard, it says that 'not' is part of the language...
I'm not sure why you didn't ask this question on comp.std.c++ instead, but...
I know... thanks for answering anyways :)
MSVC requires you #include <ciso646> to get the keyword alternatives, although I've no idea why (since I've recently started to like them).
IIRC, you can also pass /Za to the compiler to disable MS extensions, which will then re-enable these keywords. Again, don't ask me.
OK, thanks! I'll use #include <ciso646>.
One thing I'm a little curious about is whether the keywords are allowed in Boost libraries.
I want to explain why I asked. In Boost.Contract there is a limitation that every assertion must start with an alphanumeric token a-z, A-Z, 0-9 (because the assertion tokens are inspected by the pp to distinguish between normal assertions, static_assert ..., const ..., if..., using ..., namespace ..., typedef ..., etc and the pp inspection relies on concatenating the assertion tokens with a special macro identifier SPECIAL_ID ## assertion-tokens). Therefore, the following assertion expression will generate a pp error because of the leading non-alphanumeric token `!`: precondition( !empty() ) This is actually not a big deal at all because programmers can simply rewrite such an assertion in any of the following ways that will all compile with Boost.Contract: precondition( not empty() ) precondition( bool(!empty()) ) precondition( empty() == false ) Now, `bool(!empty())` is the most general (it will work with /any/ assertion expression, for example precondition( *this == *result ) /* error */ --> precondition( bool(*this == *result) ) /* ok */) but I find `not empty()` to be the most readable-- as long it is portably supported by compilers, hence my question. Thanks a lot! --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/the-not-keyword-tp3865759p3867513.html Sent from the Boost - Dev mailing list archive at Nabble.com.