There's some example code here - albeit for the MFC wrapping of the control, but MFC is usually just a thin wrapper around the API.
MSDN sample code

Igor Korot
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Hi, ALL,
Is there a place where I could see a sample code for usage of https://learn.microsoft.com/en-us/windows/win32/msi/maskededit-control?
Thank you.
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@RLWA32 ,
Yes, I understand that. But looking at its usage may give some idea of how to make it work.
Also, I think there was an implementation of masked text control in Win API. Or my memory is playing with me? Or that was an MFC implementation? The one that is referenced below...
Thank you.
Yes, I think you are probably confusing the MFC control with the Win32 API. The MFC control is derived from CEdit which is the MFC class that encapsulates the Win32 Edit control