midl_user_allocate attribute

The midl_user_allocate function is a function that client and server applications provide to allocate memory.

void __RPC_FAR * __RPC_API midl_user_allocate (size_t cBytes);

Parameters

cBytes

Specifies the count of bytes to allocate.

Remarks

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 when dealing with objects referenced by pointers:

• The server application should call midl_user_allocate to allocate memory for the application—for example, when creating a new node.
• The server stub calls midl_user_allocate when unmarshaling pointed-at data into the server address space.
• The client stub calls midl_user_allocate when unmarshaling data from the server that is referenced by an out pointer. Note that for [in], [out], and [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 must return a NULL pointer.

It is recommended that midl_user_allocate return a pointer that is 8 bytes aligned.

Examples

#include <windows.h>

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

See also

allocate

arrays

Arrays and Pointers

Array and Sized-Pointer Attributes

in

midl_user_free

/osf

out

ptr

ref

unique