Designing Local ACM Drivers

Local ACM drivers are available only to a specific application. The application must explicitly add the driver to the ACM’s list of available drivers with a call to acmDriverAdd, which is exported by the ACM and described in the Win32 SDK. If you are writing a local ACM driver, you can locate your driver code in your application or in a separate DLL file.

Including ACM Driver Code in an Application

If you include ACM driver code within an application, the application must define a DriverProc function that recognizes ACM driver messages. To access the ACM driver code, your application must:

• Call acmDriverAdd, specifying it’s own module handle as an input parameter.

• Communicate with the driver code by calling the ACM’s API functions.

• Call acmDriverRemove when it has finished using the ACM driver code.

Providing a Local ACM Driver as a Separate DLL

If you provide a local ACM driver as a separate DLL, your application must call LoadLibrary (see the Win32 SDK) to load the driver. The driver must define a DriverProc function that recognizes ACM driver messages. After the driver has been loaded, it must:

• Call acmDriverAdd, specifying it’s own module handle as an input parameter.

• Respond to ACM driver messages received when the application calls the ACM’s API functions.

• Call acmDriverRemove when the application signals that it has finished using the driver.