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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: How to compile several C files
Date: Tue, 07 Feb 2017 09:22:35 -0800
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"James R. Kuyper" <jameskuyper@verizon.net> writes:
[...]
> All of the following are object definitions. They do NOT belong in a 
> header file - you need to move each of these definitions to one or the 
> other of the *.c files. If an object's name is used in both *.c file, 
> you should have a declaration for that object in one of the two header 
> files. But that declaration would look different from from these 
> definitions. At a minimum, you would put "extern" at the beginning of 
> each declaration. Also, for the arrays, it's not necessary to put the 
> actual number of elements in the object declaration, only in the object 
> definition.

It's not necessary to include the length in the declaration.  For example
you could have
    extern balance bal[];
in a .h file and
    balance bal[YEARS];
in the corresponding .c file.

But *if* it makes sense to declare an array object in a header, then
it's not necessarily a bad idea to include the bounds in the
declaration.  It lets you use `sizeof bal / sizeof bal[0]` to compute
the number of elements, for example.

On the other hand, it's likely better not to make the array object's
name globally visible in the first place.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"