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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| Previous identifier must be a pointer |
 Posted: Tue Aug 01, 2006 12:58 am |
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hi all..
i cant understand what this error indicate!!!
| Code: | Previous identifier must be a pointer
A -> may only be used after a pointer to a structure. It cannot be used on a structure itself or other kind of variable.
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help ,,...please  |
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Ttelmah
Guest
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| Posted: Tue Aug 01, 2006 4:21 am |
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What it says.....
If you have a structure:
| Code: |
structure demo_struct {
int8 val1;
int16 val2;
} fred;
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Then you can access the elements in 'fred', with:
fred.val1
and
fred.val2
However if you take the _address_ of this structure, you can use this with:
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struct demo_struct * pointer_to_fred;
pointer_to_fred=fred;
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Then:
pointer_to_fred->val1
and
pointer_to_fred->val2
Will access the same elements. The '->' construct, accesses the element in the structure _addressed_ by the value in from of the construct.
However:
fred->val1
or
fred->val2
Will give the error message you are getting. This is because 'fred', when used to access a value, is the structure, not the address of the structure (though C allows the name on it's own to be used to represent the address, as is ued to put the address into 'pointer_to_structure'...).
You are using the '->' construct with an element in front, that is not the address of (pointer to) a 'structure' (or union).
Best Wishes |
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