Some error conditions, such as general protection violations, cause OS/2 to display a pop-up screen containing information about the error. An application can use DosError to disable error pop-up screens. Typically, a Presentation Manager application would disable error pop-up screens if it sets up its own routines to handle errors that would ordinarily generate pop-up screens.
DosError is also used to control and disable hard errors, which usually have to do with reading from and writing to disks.