LINK /OV[ERLAYINTERRUPT] Option, Valid Interrupt Numbers

The information in this article applies to:

• Microsoft LINK for MS-DOS, versions 3.x, 4.x, and 5.x

The Microsoft LINK /OV[ERLAYINTERRUPT] option specifies the interrupt number used to pass control to an overlay in an application. By default, an application uses Interrupt 3Fh (63 decimal) for this purpose. Normally, an application uses the default interrupt unless one overlaid program spawns another overlaid program.

The /OV option supports interrupts 0h through FFh (0 through 255 decimal). However, take care to avoid using any interrupts that conflict with MS-DOS. Such a conflict can be very difficult to debug. Interrupts 3Ch through 43h (60 through 67 decimal) are available as user-defined overlay interrupts without conflicting with MS-DOS. Consult an MS-DOS programmer's reference for additional information on the available interrupts.

In Microsoft LINK versions 5.3 and later, the minimum unique abbreviation for /OVERLAYINTERRUPT changed from /O to /OV.