DWORD MAKEMCIRESOURCE(wReturn, wResource)
This macro creates an unsigned long integer by concatenating the two integer values specified by the wReturn and wResourceD parameters.
UINT wReturn
Specifies the low-order word of the new long value.
UINT wResource
Specifies the high-order word of the new long value.
Specifies an unsigned long-integer value.
When you use an MCI data 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 field is set to the resource string ID. The low-order word of the return field is set to the return value. The MAKEMCIRESOURCE macro will combine these values for the DWORD return value used in the data structure.