The code page changed hook notifies an application when the code page associated with the specified message queue has been changed. The system calls a code page changed hook function after setting the new code page. Typically, the code page changed hook is used in applications that support multiple languages. The following code shows the syntax for a code page changed hook function:

VOID EXPENTRY CodePageChangedHook(HMQ hmq,
                                  USHORT usOldCodepage,
                                  USHORT usNewCodepage);

The hmq parameter receives the handle of the message queue that is changing its code page. The usOldCodepage is the code page identifier of the previous code page.

The usNewCodepage parameter is the identifier of the new code page.

A code page changed hook function does not return a value, and the system always calls the next function in the chain.