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Q74040: Ownership of Global Memory Allocated by a DLL

Article: Q74040
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SUMMARY
=======

In the Microsoft Windows environment, when a function in a dynamic- link library
(DLL) calls the GlobalAlloc function without specifying the GMEM_DDESHARE flag
in the wFlags parameter, the returned global memory object belongs to the
currently active instance of the application that called the DLL. If that
instance of the application terminates, the memory is freed. If the DLL is
unloaded before the application terminates, the memory remains allocated.

If the function specifies the GMEM_DDESHARE flag when calling the GlobalAlloc
function, the DLL owns the returned memory object. The memory is freed when the
DLL is unloaded, not when any application terminates.

This behavior will continue for 16-bit applications in all future versions of the
Microsoft Windows graphical environment. However, applications written for
Windows NT may be required to free GMEM_DDESHARE memory explicitly by calling
the GlobalFree function. In other words, the system may not free GMEM_DDESHARE
memory when either the DLL or the application terminates.

Additional query words: 3.00 3.10

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Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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