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Ask the Wizard Questions

Accvio in shareable image

The Question is:


I have a got a strange problem.

Problem Description:

XX is a sharable image. It is loaded by a main exe and the control is given to the sharable image XX. XX loads sharable image y using lib$find_image_symbol.

The link script for XX contains symbol vector options for sharable image y to recognise these symbols.

Now I have got a strange problem i.e

When XX is built in non debuggable mode there is an access violation in image XX.

This does not happen if XX is built in debug option.

Can you please suggest if there is any link option to resolve this issue ?

The Answer is:

Often side effects seem to go away when the image is relinked with debugging enabled. The side effect ends up modifying a different piece of data that is apparently not critical due to the shifting of address space assignments.

These problems can be difficult to diagnose. The side effect could have happened many instructions earlier. Sometimes you can get a clue from the contents of the registers at the time of the accvio. Something being used as an address which looks suspiciously like ASCII for example.

In source debugging hooks can make the side effect move too but if they don't for you then use them in favor over the debugging utility. Perhaps the DELTA debugging utility could be used.