Thread: MSVC debugger showing inconsistencies with dynamic arrays? Or is it bad code?

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    Registered User Chris87's Avatar
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    MSVC debugger showing inconsistencies with dynamic arrays? Or is it bad code?

    I've been trying to write a new importer for Assimp (Home). It seems ready for debugging, so I wrote a unit test for it. It fails with an access violation exception, so I started the debugger and breakpointed a few areas of interest.

    I'm trying to use a for-loop to read in a number of pairs of unsigned 4 byte integers (type IDs and offsets) with the total count for each being the variable `mh->sectionCount`.

    My problem is that when I execute this part of the code in the debugger, `mh->sectionCount` has a value of 7, but both `offsets` and `types` arrays are showing only one value entry each, even though the memory region for `types` (highlighted in screenshot) reflects 28 total bytes read in. I forgot to show this, but the variable `b` in the for-loop does go up to 6 as expected.

    TL;DR: I think the MSVC debugger display of locals in regards to dynamically allocated arrays is utterly bugged, but I'd like to make sure it's that and not just a mistake in my code. I cannot debug Assimp with MinGW because its linker has issues.

    MSVC debugger showing inconsistencies with dynamic arrays? Or is it bad code?-untitled-jpg
    Last edited by Chris87; 05-10-2018 at 07:42 PM.

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    Maybe I'm misunderstanding you, but are you saying that you expect the lower display of Locals to show multiple values for types and offsets? They aren't really arrays, though. They are pointers that you allocated a chunk of memory to. The debugger doesn't know what use you've put the memory to.
    The world hangs on a thin thread, and that is the psyche of man. - Carl Jung

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    Registered User Chris87's Avatar
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    Ooooh, okay. So since they're pointers, it'll only show the first value being pointed to?

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    I believe what it's showing is not the first value, but the address that's been assigned to the pointer. That's it.
    The world hangs on a thin thread, and that is the psyche of man. - Carl Jung

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