Databases
StackOverflow2013
Postsdbo
POAccess Violation calling imported function
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POAccess Violation calling imported function
    primarykey
    data
    text
    <p>I've got a function imported from a DLL. I control the source of both the host executable and the dynamic library. Now, in DLLMain then I used MessageBox to pop up the address of the function I'm exporting, and compared it using a breakpoint to the function pointer returned by GetProcAddress, and they're identical. </p> <p>However, when I try to call the function, I get an access violation. The function in question just returns NULL and has no logic, so it can't be thrown by the function specifically. </p> <p>How can calling a known valid function pointer, with the correct signature, and verified safe logic, yield an access violation?</p> <p>Edit: Information gained through another separate question about why the debugger is dying in this situation suggests that my stack is being smashed too? That would make more sense than an AV, but the function pointer and the function are completely compatible and the address is correct.</p> <pre><code>extern "C" Render* __cdecl CreateRender(WindowsOS* ptr) { return nullptr; } typedef Render*(__cdecl *RendererCreateFunction)(WindowsOS*); </code></pre> <p>I used a simple, small piece of code in DLLMain to qualify that they are in fact compatible as far as the compiler is concerned.</p> <pre><code>BOOL WINAPI DllMain( __in HINSTANCE hinstDLL, __in DWORD fdwReason, __in LPVOID lpvReserved ) { RendererCreateFunction func = &amp;CreateRender; } </code></pre> <p>If they aren't compatible (they include the same header) then the compiler should throw an error and refuse to build the DLL, but it accepts this just fine.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USPuppy
    1. USPuppy
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POAccess Violation calling imported function
      1. This table or related slice is empty.
      1. VTUpMod
    1. COMaybe the calling conventions are inconsistent?
      singulars
      1. POAccess Violation calling imported function
      1. USVlad
    2. COIt was default calling convention. I explicitly specified `__cdecl` on both sides, same effect
      singulars
      1. POAccess Violation calling imported function
      1. USPuppy
    3. COare both part assembled for one architecture in one mode(debug|release) and with one multithreading setting(mt|mtd|etc)?
      singulars
      1. POAccess Violation calling imported function
      1. USRaiv
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload