From:	e DOT d DOT k DOT i DOT s DOT e DOT r AT j DOT a DOT x DOT n DOT e DOT t DOT c DOT o DOT m (M. Edward Kiser)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Precompiled headers.
Date:	Sat, 21 Jun 1997 19:09:52 GMT
Organization:	Southeast Network Services, Inc.
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References:	<5oe8hq$25a AT lion DOT cs DOT latrobe DOT edu DOT au> <33AAD839 DOT 34ED AT cs DOT com>
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To:	djgpp AT delorie DOT com
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"John M. Aldrich" <fighteer AT cs DOT com> wrote:

>Gregary J Boyles wrote:
>> 
>> Does DJGPP have them?

>What are they?  And why would you want them?  Headers get inserted into
>your code by the preprocessor and compiled along with the rest of your
>program.  I'm afraid that I don't understand what you're asking.

To answer the second question, pre-"compiled" headers are actually
pre-PARSED headers. To generate a pre-"compiled" header file, the
compiler dumps its symbol table after parsing the header files; to use
it, the compiler merely reads this symbol table back in instead of
parsing the header files again. Obviously, this is only useful if you
have a lot of CPP files that #include the SAME headers in the SAME
order. But many programs do this, especially with large complicated
header files like windows.h, the Standard Template Library, or any
large windowing framework such as SWORD or OWL. Pre-compiled headers
can speed things up a LOT.

To answer the first question, DJGPP does not have them, but I think
they would be a very nice addition to GCC on ALL platforms.
--------
Ed Kiser ( e d k i s e r @ s o u t h e a s t . n e t )
"The man who does not read good books has no advantage over
the man who can't read them." -- Mark Twain

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