Message duration parameter
Applications typically use pop-up windows to briefly display important notification messages to the user. An application creates the window, displays it for an application-defined duration, and then destroys the window.
Because users with visual impairments or cognitive conditions might need more time to read notification pop-ups, applications should not hard code the duration. Instead, an application should set the duration based on the value of the SPI_GETMESSAGEDURATION system parameter. To retrieve this parameter, use the SystemParametersInfo function.
Assistive technology applications can set the message duration, based on user input, by setting the SPI_SETMESSAGEDURATION system parameter.