On Mon, 4 Nov 2013, Jonathan Wakely wrote: > On 28 October 2013 21:13, Ian Lance Taylor wrote: >> I don't have any strong objection, but I'll note that it's even easier >> to use -D options. >> >> CC='gcc -D__DATE__=today' > It's undefined behaviour in both C and C++ to redefine pre-defined > macros such as __DATE__ or __TIME__. > > The undefined behaviour study group of the C++ committee are > considering making it ill-formed, which would require a diagnostic.
Also, that would not warn, but change the outcome of the program. (Which could be one way to address this, of course, but the request we had really was about warning.) Gerald
