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

FROM : Ole Voss
DATE : Sun Oct 31 16:18:17 2004

> 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
>
>


This also means, that I have to include the header file wherever I need it?
That could mean that the same class has to be recompiled tens of times -
right?

So what possibilities do I have to create global variables?


Regards

Ole.

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