Re: [Boost-testing] Regression testing (1.33)

From: John Maddock (john_at_[hidden])
Date: 2005-06-02 11:12:48

>> One has to wonder why the test functions in 7.1 then and fails in
>> 8.0.  Surely you don't imply that the older libraries were "better".
>
> Well, "old" CRT returned NULL when input was negative. It's documented in 
> MSDN and quite obvious when looking at source code. I dunno if returning 
> NULL makes them "better" or not; it depends on what you do with result. 
> However, if you test the result for NULL, probably you might test time_t 
> value instead for negative, before actually calling localtime?

The "new" behaviour doesn't appear to be standard conforming: time_t is an 
arithmetic type, and C99 says: "The range and precision of times 
representable in clock_t and time_t are implementation-defined", while for 
localtime it says: "returns: The localtime function returns a pointer to the 
broken-down time, or a null pointer if the specified time cannot be 
converted to local time", so the current code appears correct with respect 
to the standard.  From a practical viewpoint, I guess the question is are 
there any platforms that accept negative times?  It's not as illogical as it 
might appear if they do - it's the only way to represent dates before 1970 I 
believe.

Just my 2c worth,

John.