Technical Note PT05

MPW C Functions: To declare or not to declare, that is the question.

CONTENTS "The include files are all screwed up!" The Law References Downloadables

Here's the low-down on when C functions need not be declared in include files. [Nov 01 1987]

"The include files are all screwed up!"

This is a common misconception people have when they look through the MPW C include files. People report that the declaration of a ROM or system call foo() has been mistakenly left out of this or that include file. Here's the low-down on when functions do not have to be declared in an include file.

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The Law

A C function does not need to be declared in an include file if it requires glue code and returns a short or long integer as a result.

Routines that require glue code include:

• All routines that are marked [Not in ROM] in Inside Macintosh
• All register based routines (Operating System routines)
• All routines which have strings or points as arguments (and have mixed case spellings)

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References

MPW C Manual

Using Assembly Language

The C Programming Language, Kernighan & Ritchie

M.PT.CFuncArgs

Using Strings or Points as Arguments

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Downloadables