To share an I/O procedure with other applications, follow these guidelines:
Put the code for the I/O procedure in a dynamic-link library (DLL).
Create a function in the DLL that calls mmioInstallIOProc to install the I/O procedure.
Export this function in the module-definitions file of the DLL.
To use the shared I/O procedure, an application must first call the function in the DLL to install the I/O procedure.