Managing C/C++ Libraries: Dependencies

[David Collier-Brown]

> In article <124300001 at inmet> stt at inmet writes:
>>A simple language extension would be:
>>
>>#include_once "classname.h"
[definition of include_once as equivalent to
 #ifdef classname_h
 #  include "classname.h"
 #  define classname_h
 #endif
]

>From article <8387 at nlm-mcs.arpa>, by mjr at vax2.nlm.nih.gov.nlm.nih.gov (Marcus J. Ranum):
> 	I wonder how much code would break is such an extension were added,
> and the #include_once were made the DEFAULT rather than the exception ? 

  I suspect very little: I used such a construct in a preprocessor
for multiple languages without further thought, and my C programs
tend to work correctly (they may, in fact, therefor be incorrect
:-). I'm crossposting the question to comp.lang.c for further
discussion.

 Ok, people! Would this change, made silently, injure correct
programs?  It is admitted that it may allow incorrect programs to
compile, but that isn't waht I'm concerned about.
  Specifically, what about include trees which cannot be tsorted?

--dave c-b