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RE: reduce compilation times?
- From: "Duft Markus" <Markus dot Duft at salomon dot at>
- To: "Tom St Denis" <tstdenis at ellipticsemi dot com>
- Cc: "Fabian Cenedese" <Cenedese at indel dot ch>, <gcc-help at gcc dot gnu dot org>
- Date: Wed, 28 Nov 2007 14:51:07 +0100
- Subject: RE: reduce compilation times?
> This is where automated tools come in handy. In my projects, I have
> scripts that pick up source files and insert them into the
> makefile(s). So with very little fuss I can add new files (either new
> functionality or new split up code).
> It really depends on the size of the class whether factoring makes
> sense or not. but if you have heaps of 3000+ line long functions, I
> suspect you spend enough time searching through them as is.
> When I was working on DB2 and scouring their often 6000+ line files
> looking for why GCC 4.whatever.beta wasn't working as hot as it could,
> it wasn't exactly a lot of fun.
I agree with such big files beeing no fun at all. I managed to keep a
structure where files don't get longer than say 500 lines.
>> BTW: has gcc a mechanism to determine, wether a change in a header
>> file affects a particular .cpp file? Microsoft has... They skip
>> every file where no affecting changes are detected...
> Can't a makefile do that?
> file.o: file.H file.C
> Yes that works fine with GNU Make
> -bash-3.1$ make
> make: `ctmp1.o' is up to date.
> -bash-3.1$ touch ctmp.H
> -bash-3.1$ make
> g++ -c -o ctmp1.o ctmp1.C
> -bash-3.1$ cat Makefile
> ctmp1.o: ctmp.H ctmp1.C
> It's almost like, if you engineer your builds correctly, these are
> I don't want to make this personal, but honestly, if you're going to
> try and give out advice, at least know what you are talking about.
> There are actual proper ways to do things that reduce errors, increase
> productivity, etc, etc.
You didn't get the question: i was asking if a *change* in a header is
recognized to affect a *certain* .cpp file, not how make handles
dependencies and updates targets. Micorosft recognizes that a change in
a certain struct inside a header file may not require a recompilation of
a certain .cpp file if it doesn't use that struct. Thats what i asked
Also i have absolutely no problem with managing my builds correctly. One
part of my job is organizing, managing and building about 80 software
As far as getting personal is concerned: You are free to get personal if
you like, still i really know very well what i'm talking about, since im
make my money with this. You can easily recognize things that i don't
know by those question marks behind my sentences.
5. Dezember 2007
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