On 24 May 2012 20:26, Peter A. Felvegi wrote: > Hello, > > I'm not sure whether this is standard behaviour or not; nonetheless I was > quite surprised:
Please note that "is this valid" questions are not appropriate on this mailing list, please use the gcc-help mailing list for questions about using GCC or a general C++ forum, thanks. There are (at least) two high-quality online compilers you can use to see whether something you find surprising is a GCC bug or not: http://comeaucomputing.com/tryitout/ http://llvm.org/demo/ They both agree with GCC. > Somewhat connected question: if I use |-Wzero-as-null-pointer-constant to > detect cases where 0 means null pointer, shouldn't there be a switch that > forbids conversion from 0 to null ptr? IMHO no. The warning issues a diagnostic that may be desirable for style reasons, your suggestion alters the language and makes any program relying on it non-portable. You can make it an error with -Werror=zero-as-null-pointer-constant but that doesn't resolve any ambiguity. > I have a class that has operator() > overloaded for size_t and for const char* (access elements by index or by > name). All is well, except for the index 0: the call would be ambiguous. I > tried to trick this with 0+0, etc, hence the whole post. 0.0 works, though. > Any better ideas? Explicit cast? Yes,an explicit cast works, or a literal that doesn't require conversion, e.g. 0ul (assuming size_t is a synonym for unsigned long) or an enumerator with value zero which would only allow conversion to size_t, or in C++11 use the keyword nullptr.
