Q40408: Setting the Overlay Interrupt (/O) in LINK
Article: Q40408 Product(s): See article Version(s): 3.61 3.65 Operating System(s): MS-DOS Keyword(s): ENDUSER | docerr | mspl13_basic Last Modified: 20-JAN-1989 Question: Page 272, Section 12.2.12, of the "Microsoft CodeView and Utilities Software Development Tools for the MS-DOS Operating System" manual states that you can change the default overlay interrupt. The default interrupt is 3F hexadecimal. Is the manual correct? Do you have to change the interrupt if you have a program that uses overlays and it spawns a program that also uses overlays? Doesn't the compiler save interrupts? Suppose both Programs A and B use overlays and A spawns B. If B is a Microsoft C Version 5.00 or 5.10 program, shouldn't it restore the original INT 3F address when it exits? Thus, everything should work correctly without /OVERLAYINTERRUPT. Response: You are correct; the C Versions 5.00 and 5.10 compiler saves and restores the interrupt so there should be no conflict. The C Versions 5.00 and C 5.10 manual is incorrect. This switch need only be used if you are linking a program with overlays, and INT 3F is being used by something else when you run the program. For example, INT 3F might be used to communicate with a hardware board or a TSR might use it; however, this is unlikely. This option is for advanced users who know their configurations well enough to know who is using which interrupt vectors and know there is a conflict.
THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.
Copyright Microsoft Corporation 1986-2002.