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Re: Where to include header files - relates to last question on variable scope

On Oct 31, 2004, at 12:43 AM, Ole Voss wrote:
Why do I have to include the header file of this singleton class in every
other class I use it in? Should the class not be available to the compiler
the moment it's included in the 'main.m'?

There is nothing special about a file named "main.m" in the compiler's eyes, so no, the class should not be available everywhere just because its header is included in a file named "main.m".

I'm missing something fundamental here - it's always like that :-)

Independent compilation. Essentially, the compiler is called once per implementation (.m, .c, .cpp, etc.) file and must be provided with a file that is both syntactically correct *and complete* in order to generate an object file. This is generally done by using the C preprocessor, via the #include or (in Objective-C) #import directive to bring in the text of another file.

Java is different, it actually has the compiler do all of the necessary package/class dependency tracking and examine other implementation and class and jar files, compiling additional implementation files into class files as necessary.

-- Chris

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 >Where to include header files - relates to last question on variable scope (From: Ole Voss <email@hidden>)



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