[comp.lang.c] C Style check cpp symbol to decide file inclusion

lew@gsg.UUCP (Paul Lew) (01/13/89)

In article <2688@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>graphics.h:
>	#ifndef GRAPHICS_H
>	#define GRAPHICS_H
>	...
>	#endif

This is a typical C hack.

Sometimes ago when we were porting X11R2 to MSDOS environment, we found out
that it took a LONG time to compile every file.  One reason was because there
were lots of this kind of mechanism in X11R2 include files.  This will make
programmers' life easier but really slow down the compilation time.  For
complicated software system like X, many include files will be read and
then ignored for every cc.

My personal opinion: I will try not to use it if possible and hope that
sometime someone will give us a better solution.
-- 
Paul Lew			{oliveb,harvard,decvax}!gsg!lew	(UUCP)
General Systems Group, 5 Manor Parkway, Salem, NH 03079	(603) 893-1000

peter@ficc.uu.net (Peter da Silva) (01/16/89)

In article <293@gsg.UUCP>, lew@gsg.UUCP (Paul Lew) writes:
> Sometimes ago when we were porting X11R2 to MSDOS environment, we found out
> that it took a LONG time to compile every file.  One reason was...
> ... many include files will be read and
> then ignored for every cc.

Which is why the Amiga include files explicitly put that #ifdef before each
nested include that everyone has been questioning.
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Work: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.   `-_-'
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