Re: Time Stamping Again.

[Dirk Heinrichs <dirk.heinrichs@altum.de>]

Austin Obyrne wrote:

> To me this is more a passing curio that seems to be going unnoticed by
> many users of language compilers.
> 
> It has been put there for a purpose no doubt and I speculate on at least
> one good use to which it may be put !

It's not really going unnoticed. It is a standard feature of any C/C++ 
compiler provided via the __TIME__ and __DATE__ macros. But in most cases, 
it is considered harmful. Let's think about software development in larger 
teams. Let's also assume that it is vital for fixing bugs to be able to 
exactly and verifiably reproduce past builds.

So you do a release build and create checksums of your .o files. When you 
need to reproduce that builds a year or two later, you can again create 
checksums and check them against the original ones to make sure you've built 
exactly what the customer has.

Now, when above macros have been used to record compilation time and date in 
your .o files, you'll always have a checksum mismatch and you can never be 
sure that you've built again what has been built before.

So checksums are, as others have already pointed out, the far better 
alternative, because a checksum always stays the same for the same 
compilation, but a timestamp does not.

Bye...

	Dirk
-- 
Dirk Heinrichs <dirk.heinrichs@altum.de>
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