C Useful

Windows (Misc)

Format And Print Last Error Message
Convert A Windows GUID To A String (char *)
Convert In UTF-8, A String (char *) To (wchar_t *)
[OR] A String (wchar_t *) To (char *)
List Input/Output Audio Devices (MMDevice API)
List Input Video/Audio Devices (DirectShow)
ANSI To UNICODE Functions

Format And Print Last Error Message

( MSDN GetLastError | MSDN FormatMessage )

Convert A Windows GUID To A String (char *)

( MSDN GUID )

Convert In UTF-8, A String (char ) To (wchar_t )
[OR] A String (wchar_t ) To (char )

( MSDN MultiByteToWideChar | MSDN WideCharToMultiByte )

List Input/Output Audio Devices (MMDevice API)

( MSDN IMMDevice )

List Input Video/Audio Devices (DirectShow)

( MSDN ICreateDevEnum::CreateClassEnumerator )

ANSI To UNICODE Functions

( MSDN <function> )