_RegQueryValueEx

DWORD _RegQueryValueEx(HKEY hKey, LPSTR lpszValueName, 
      LPDWORD lpdwReserved, LPDWORD lpdwType, LPBYTE lpbData, 
      LPDWORD lpcbData)
 

Retrieves the value for the given registry key for the given value name.

hKey
Handle of a previously opened key or one of the predefined root keys given in Predefined Keys.
lpszValueName
Address of a null-terminated string specifying the value name to for which to retrieve the value. Can be NULL or point to a NULL-string.
lpdwReserved
Reserved; set to NULL.
lpdwType
Address of a 32-bit variable that receives the data type for the given value. Can be NULL if data type is not needed.
lpbData
Address of a buffer that receives the value data for given registry key.
lpcbData
Address of a 32-bit variable that contains the size, in bytes, of the lpbData buffer. This variable receives the size, in bytes, of the retrieved data.