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Annotation of mstools/samples/gdidemo/wininfo.c, revision 1.1.1.2

1.1.1.2 ! root        1: 
        !             2: /******************************************************************************\
        !             3: *       This is a part of the Microsoft Source Code Samples. 
        !             4: *       Copyright (C) 1993 Microsoft Corporation.
        !             5: *       All rights reserved. 
        !             6: *       This source code is only intended as a supplement to 
        !             7: *       Microsoft Development Tools and/or WinHelp documentation.
        !             8: *       See these sources for detailed information regarding the 
        !             9: *       Microsoft samples programs.
        !            10: \******************************************************************************/
        !            11: 
1.1       root       12: /*---------------------------------------------------------------------------*\
                     13: | WINDOW INFORMATION MODULE
                     14: |   This module contains the routines which deal with obtaining the extra
                     15: |   object information associated with a window.  For these to work, the
                     16: |   window class must reserve the 0th word of the win-class object to be
                     17: |   used to hold global-memory handle.
                     18: \*---------------------------------------------------------------------------*/
                     19: 
                     20: #include <windows.h>
                     21: #include "gdidemo.h"
                     22: 
                     23: /*---------------------------------------------------------------------------*\
                     24: | ALLOC WINDOW INFO
                     25: |   This routine allocates memory out of the application heap for storing
                     26: |   extra memory for the window.  It is alway referenced as offset 0.
                     27: \*---------------------------------------------------------------------------*/
                     28: BOOL FAR AllocWindowInfo(HWND hWnd, WORD wSize)
                     29: {
                     30:     HANDLE hsd;
                     31: 
                     32: 
                     33:     if(hsd = LocalAlloc(LHND,(WORD)wSize))
                     34:     {
                     35:         SetWindowLong(hWnd,0,(LONG)hsd);
                     36:         return(TRUE);
                     37:     }
                     38:     return(FALSE);
                     39: }
                     40: 
                     41: 
                     42: /*---------------------------------------------------------------------------*\
                     43: | LOCK WINDOW INFO
                     44: |   This routine de-references the extra-memory associated with the window.
                     45: |   it locks the object and gives the caller a pointer to the memory.
                     46: \*---------------------------------------------------------------------------*/
                     47: PVOID FAR LockWindowInfo(HWND hWnd)
                     48: {
                     49:     HANDLE hMem;
                     50:     PVOID  pMem;
                     51: 
                     52: 
                     53:     pMem = NULL;
                     54:     if(hMem = (HANDLE)GetWindowLong(hWnd,0))
                     55:         pMem = (PVOID)LocalLock(hMem);
                     56: 
                     57:     return(pMem);
                     58: }
                     59: 
                     60: 
                     61: /*---------------------------------------------------------------------------*\
                     62: | UNLOCK WINDOW INFO
                     63: |   This routine unlocks the memory the caller has previously locked.
                     64: \*---------------------------------------------------------------------------*/
                     65: BOOL FAR UnlockWindowInfo(HWND hWnd)
                     66: {
                     67:     HANDLE hMem;
                     68: 
                     69: 
                     70:     if(hMem = (HANDLE)GetWindowLong(hWnd,0))
                     71:         if(!LocalUnlock(hMem))
                     72:             return(TRUE);
                     73: 
                     74:     return(FALSE);
                     75: }
                     76: 
                     77: 
                     78: /*---------------------------------------------------------------------------*\
                     79: | FREE WINDOW INFO
                     80: |   This routine frees the object memory associated with the window.
                     81: \*---------------------------------------------------------------------------*/
                     82: BOOL FAR FreeWindowInfo(HWND hWnd)
                     83: {
                     84:     LOCALHANDLE hMem;
                     85: 
                     86: 
                     87:     if(hMem = (HANDLE)GetWindowLong(hWnd,0))
                     88:         LocalFree(hMem);
                     89:     return(TRUE);
                     90: }

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