🚀 go-pugleaf

> =========="Charles F. McDevitt", 2/2/96==========
 
> Marek MAKOWSKI wrote:
 
> > Would not it be sensible to add to the preprocessing a directive
> > that would stop processing the current file ? Something like
 
> > #ifdef XXXX
> > #exit
 
> > this would safe processing (sometimes very long) file in the common
> > situations:
 
> > #ifdef XXXX
> > // a (possibly) long header file hear
> > #endif  /* ifdef XXXX*/
 
 
> Wouldn't it be better to update the C++ standard so the
> default is that include files only get included once, and the
> compiler/preprocessor keeps track of which ones it's already 
> seen.  Then we wouldn't have to mess with these ugly #ifdefs
> to make include files only be included once.

Nothing requires a "header" file to generate the same thing
each time it is included.  For most common uses, that is the
desired semantics, but the current approach allows other
semantic situations to be handled by the existing mechanism
(though the #include is not parameterized, and so "globalish"
name techniques are needed to do other semantics.  But an
include file can be a form of template for source construction
that could be included many times on purpose.  That is what
you are proposing to eliminate.  So you have to debate the
desirability of this style of include file use.  Since C allows it,
this would be a departure in a definite compatibility area.

I express no opinion of the desirability of this.  I am merely
trying to clarify the underlying issues.

Good Day
Dick
Dick.Menninger@DaytonOH.ATTGIS.COM


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