INF: Ownership of Global Memory Allocated by a DLL

ID Number: Q74040

3.00 3.10

WINDOWS

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 reference words: 3.00 3.10 shared