Text 12, 62 rader
Skriven 2004-07-25 18:57:00 av Neil Heller (1:106/2000.0)
     Kommentar till text 11 av Bgpartri@Ca.Inter.Net (1:261/38)
Ärende: [C] Code File Structure
===============================
TO: BGPARTRI@CA.INTER.NET


BP>I'm interested in finding a document or book that explains 
BP>how to split modules into files.  I have done several 
BP>different things, and none of them seem perfect.

In the C texts that I've seen there hasn't been any discussion of the 
subject.  In the C++ books that I've seen there has only been 
instruction by example.  Do you program in COBOL?  If so, the best 
correspondence I can think of is everything in the DATA DIVISION goes 
into the header and everything in the PROCEDURE DIVISION goes into the 
.cap file.

All the "modern" languages do things differently (Java vs. C++ vs. 
smallTalk...etc.) so for anything new and exotic the best reference is 
your experience and intuition.  BTW, there is no mandatory placement of 
that which must go into a header file vs. anywhere else.  The compiler 
(in most cases) doesn't care.  Just so long as it knows "who's on first" 
when it's asked to deal with something.

BP>Global and local variables seem to be obvious, but where is the
BP>"normal"  place to put hardware defines.  For example, I use hardware
BP>defines that only apply if I have a certain type of 
BP>temperature sensor.  A different sensor uses different 
BP>defines.  Should these be in a global hw.h file or in the 
BP>module code file.

This sound like something polymorphism should handle - so C++ with its 
classes would be the obvious choice (or any object oriented language).

BP>And where do you define enums that are used in several 
BP>modules.

My suggestion would to be one header file that's "include"d in all the 
modules that need it.  One caveat though, that one header file (well, 
actually every header file should include the same) must look like this:

#ifndef <header-file-name + date + time>        // to make it unique
#define <header-file-name + date + time>

<header-file-body-goes-here>

#endif

That guarantees that the header file in question is only included once.

BP>I also have questions about reusable code, and how to 
BP>optimally split up the files.

If you have a chunk of code, the chances are that only a part of that 
chunk will be reusable.  The part that's reusable should go into its own 
file(s) where it can be called as an include.  If the whole chunk is 
reusable put it all into its own file(s) (under the guidelines given 
above).

I hope this gives you some ideas.

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