🚀 go-pugleaf

In article <726351962snz@chrism.demon.co.uk> chris@chrism.demon.co.uk writes:
>In article <1993Jan6.084522.25921@emr1.emr.ca> jagrant@emr1.emr.ca writes:
>
>>At the risk of appearing stupid again, I have another (perhaps
>>obvious, but not right now at 3:30 AM) question...
>> [ Lots of stuff deleted]
>>
>>So, can someone tell me the difference between the following 2
>>statements:
>>        extern STUFF *stufftable;
>>        extern STUFF stufftable[];
>>with respect to the code generated when I reference stufftable, i.e.:
>>        stufftable[i].xxx=...
>>and explain why it is so dangerous here, but it's perfectly ok
>>to use a pointer or a [] in a function declaration.
>>-- 
>>John A. Grant                                           jagrant@emr1.emr.ca
>>Airborne Geophysics
>>Geological Survey of Canada, Ottawa
>>
>
>The difference is very simple:
>
>    extern STUFF *stufftable
>
>tells the complier that you have a global variable which is a POINTER to
>a "stufftable".  ie, the global quantity is a 2 or 4-byte pointer.
>
>    extern STUFF stufftable[]
>
>tells the compiler that you have a global ARRAY of STUFFs.
>
>The two things are totally different.  The reason that it doesn't matter
>in a function declaration is that passing the name of an array to a function
>is the same as passing a pointer to the start of the array.
>
>Hope this helps,


		Yes, it's me again and less stupid...
		Thanks to all you responded.  The essential
		difference is that:
			extern STUFF stufftable[];
		assumes that stufftable resides in the current
		data segment, when in fact it is a pointer to
		the stuff on the heap.
-- 
John A. Grant						jagrant@emr1.emr.ca
Airborne Geophysics
Geological Survey of Canada, Ottawa