midl_user_allocate

void __RPC_FAR * __RPC_USER midl_user_allocate (size_t cBytes);

Parameters

cBytes

Specifies the count of bytes to allocate.

Both client applications and server applications must implement the midl_user_allocate function, unless you are compiling in OSF-compatibility (/osf) mode. Applications and generated stubs call midl_user_allocate directly or indirectly to manage allocated objects. For example:

• The client and server applications should call midl_user_allocate to allocate memory for the application, such as when creating a new node.
• The server stub calls midl_user_allocate when unmarshalling data into the server address space.
• The client stub calls midl_user_allocate when unmarshalling data from the server that is referenced by an out pointer. Note that for in, out, unique pointers, the client stub calls midl_user_allocate only if the unique pointer value was NULL on input and changes to a non-null value during the call. If the unique pointer was non-null on input, the client stub writes the associated data into existing memory.

If midl_user_allocate fails to allocate memory, it should return a null pointer or raise a user-defined exception.

The midl_user_allocate function should return a pointer as shown:

• For Windows NT running on Intel platforms, the pointer is 4 bytes aligned.
• For Windows NT running on MIPS and Alpha platforms, the pointer is 8 bytes aligned.
• For Windows 95, the pointer is 4 bytes aligned.
• For Windows 3.x and MS-DOS platforms, the pointer is 2 bytes aligned.

For example, the sample programs provided with the Win32 SDK implement midl_user_allocate in terms of the C function malloc:

void __RPC_FAR * __RPC_USER midl_user_allocate(size_t cBytes)
{
    return((void __RPC_FAR *) malloc(cBytes));
}
 

Note  If the Rpcss package is enabled (for example, as the result of using the enable_allocate attribute), RpcSmAllocate should be used to allocate memory on the server side. For additional information on enable_allocate, see MIDL Reference.