Re: [boost] [wave]: possible use for makefile dependencies

From: Stefan Seefeld (seefeld_at_[hidden])
Date: 2005-07-28 02:44:55

Damien Fisher wrote:
> I'm not sure I quite understand what you are asking for here...could
> you give an example?
> 
> On 7/28/05, Stefan Seefeld <seefeld_at_[hidden]> wrote:
> 
>>What would make such a tool even more useful than a replacement
>>for 'gcc -M' would be if it could generate dependencies for
>>sets of files, i.e. with the possibility of internal caching
>>such that it doesn't have to reparse a file twice if not necessary.
>>But that may require quite some work, for example to determine a 'state'
>>dependent on values of all the defined macros.

The original 'makedepend' tool was part of XFree86, I believe
(bundled with the 'imake' tool), and it was able to generate
all dependencies for a set of source files in a single run.
The result was appended to a Makefile.
The original idea to generate dependencies in a single call
instead of individually per source file was that it would be
significantly faster, mostly due to the processor's ability
to cache already processed headers, and so it didn't need to
reparse it when a second source file included it.

I'm not sure how much of an issue that today. A first step
would be to let wave generate a dependency list for a single
source file in a way that it could be used by different tools
(make, scons, bjam), and later work on the infrastructure
to allow it to efficiently process multiple source files at
once.

Regards,
                Stefan