DWORD MAKEMCIRESOURCE(UINT wReturn, UINT wResource)
This macro creates an unsigned long integer by concatenating the two integer values specified by the wReturn and wResource parameters.
wReturn
Specifies the low-order word of the new long value.
wResource
Specifies the high-order word of the new long value.
When you use an MCI structure to return integer information that also has a string equivalent, MCI needs additional information to find the string equivalent in the resource table. The high-order word of the return member is set to the resource string ID. The low-order word of the return member is set to the return value. The MAKEMCIRESOURCE macro will combine these values for the DWORD return value used in the structure.