extern char *foo vs. extern char foo[]

[Dave Eisen]

In article <1990May30.001219.23564 at uunet!unhd> rg at unhd.unh.edu.UUCP (Roger Gonzalez ) writes:
>
>According to K&R, there should be no difference between the two extern
>defs in my subject header.  In fact, the second form (char foo[]) should
>get translated into the first.  Unfortunately, it doesn't.  Here's a
>more detailed example of what I mean:
>
>FILE #1:
>
>     char hello[100];
>FILE #2:
>
>     extern char *hello;


No, these are not the same thing. char [] and char * are two different
types and funny things happen when you declare variables incorrectly.

An array is treated as a pointer to the first element when used in an 
expression or when passed as a function parameter, this does not
mean that an array and a pointer are the same thing. And (as you pointed
out) you cannot declare a variable as one and hope to get the other.


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