Go4Expert - Accessing To A Struct With A Given Pointer

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Accessing To A Struct With A Given Pointer

We have a struct defined as :

Quote:

typedef struct tagWINDOWPOS { /* wp */

HWND hwnd;

HWND hwndInsertAfter;
int x;
int y;
int cx;
int cy;
UINT flags;

} WINDOWPOS;

Then we are sent a message...

Quote:

WM_WINDOWPOSCHANGING

WPARAM wParam

LPARAM lParam;

Parameters

wParam

This parameter is not used.

lParam

Pointer to a WINDOWPOS structure that contains information about the window's new size and position.

And this is the code which gets the message

Quote:

case WM_WINDOWPOSCHANGING:

WINDOWPOS * pWinPos;

pWinPos = lParam;
break;

lParam contains the address of the struct. Here we want to access to the struct.

But there is a problem with the code. pWinPos is a constant pointer, so we can't simply assign an address to it.

So, finally, here is my question...
How can I access to the WINDOWPOS struct whose address is given by lParam

PS : I am using Dev-C++

Re: Accessing To A Struct With A Given Pointer

Welcome to the Programming forum.

Quote:

Originally Posted by AhmedHan

How can I access to the WINDOWPOS struct whose address is given by lParam

By type casting the lParam pointer to the WINDOWPOS pointer.

pWinPos = (WINDOWPOS *)lParam;

Thanks
Shabbir Bhimani

Re: Accessing To A Struct With A Given Pointer

That one works, thank you.

Actually, I tried the same thing, but I put the * oparetor to the wrong place :
pWinPos = (* WINDOWPOS)lParam; instead of pWinPos = (WINDOWPOS *)lParam;
That is silly of me :)

Re: Accessing To A Struct With A Given Pointer

Quote:

Originally Posted by AhmedHan

The silly's can come at any time and if you share the knowledge and queries with other you tend to reduce them. haha