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IMA error when dynamically loading a DLL
Posted: Sat Apr 12, 2025 7:10 am
by breeze4me
This is about a bug that has been fixed in the past.
https://www.purebasic.fr/english/viewtopic.php?t=43173
I've been testing that code and found a problem: it works fine when using the lib file, but crashes when dynamically loading the dll.
dll code:
Code: Select all
ProcedureDLL addScrollArea(hWnd)
oldGadgetList = UseGadgetList(hWnd)
gadget = ContainerGadget(#PB_Any, 0, 0, 400, 400)
CloseGadgetList()
SetGadgetColor(gadget, #PB_Gadget_BackColor, #Red)
UseGadgetList(oldGadgetList)
EndProcedure
main code(OK):
Code: Select all
Import "dll.lib"
CompilerIf #PB_Compiler_Processor = #PB_Processor_x86
addScrollArea(a) As "_addScrollArea@4"
CompilerElse
addScrollArea(a)
CompilerEndIf
EndImport
#win = 16 ;Change to 15 or less to remove the crash!
If OpenWindow(#win, 0, 0, 600, 600, "", #PB_Window_SystemMenu|#PB_Window_MinimizeGadget|#PB_Window_MaximizeGadget|#PB_Window_SizeGadget|#PB_Window_ScreenCentered)
addScrollArea(WindowID(#win))
Repeat
event=WaitWindowEvent()
Until Event = #PB_Event_CloseWindow
EndIf
main code (IMA in PB x86 / debugger crashes in PB x64):
Code: Select all
#win = 16 ;Change to 15 or less to remove the crash!
Prototype addScrollArea(a)
Define addScrollArea_.addScrollArea
If OpenLibrary(0, "dll.dll")
addScrollArea_ = GetFunction(0, "addScrollArea")
If OpenWindow(#win, 0, 0, 600, 600, "", #PB_Window_SystemMenu|#PB_Window_MinimizeGadget|#PB_Window_MaximizeGadget|#PB_Window_SizeGadget|#PB_Window_ScreenCentered)
If addScrollArea_
addScrollArea_(WindowID(#win))
EndIf
Repeat
event=WaitWindowEvent()
Until Event = #PB_Event_CloseWindow
EndIf
CloseLibrary(0)
EndIf ; Invalid memory access. (read error at address 1387796518)
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Sat Apr 12, 2025 11:05 am
by mk-soft
It doesn't work that way. A DLL has its own object management and is not coupled with the main executable.
Link:
Access gadget from libray
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Sat Apr 12, 2025 11:39 am
by breeze4me
Anyway, I found a workaround.
If the CloseLibrary(0) line is removed, there is no error.
Edit:
I tested a complex case and the workaround didn't work.
The ".lib" file must be used for this to work properly.
@mk-soft
I read that post a long time ago.
What I'm trying to do is not share the object management system, I'm just researching how to create gadgets from DLLs like the way srod used in the original post.
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Sat Apr 12, 2025 2:19 pm
by mk-soft
breeze4me wrote: Sat Apr 12, 2025 11:39 am
@mk-soft
I read that post a long time ago.
What I'm trying to do is not share the object management system, I'm just researching how to create gadgets from DLLs like the way srod used in the original post.
But the gadget is then in the wrong object list. In the DLL and not in the Main ...
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Sat Apr 12, 2025 2:52 pm
by breeze4me
mk-soft wrote: Sat Apr 12, 2025 2:19 pm
But the gadget is then in the wrong object list. In the DLL and not in the Main ...
I know. I plan to have the main code manipulate the gadgets created by DLLs in a way that calls functions inside DLLs.
This is enough to support custom gadgets via DLLs in a form designer app.
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Tue Apr 15, 2025 8:35 am
by Fred
I fixed the crash when the DLL is dynamically loaded and auto-freed at end in 6.21 beta 5 (ie: CloseLibrary() not called). But if you close the DLL before exiting, there is still some callbacks registered from the DLL in the main process and it will crash because the window will try to call the callback when doing its cleanup. So you can either let the program unload the DLL automatically at end or close all the windows before calling CloseLibrary().
Re: [6.21 b4] IMA error when dynamically loading a DLL
Posted: Tue Apr 15, 2025 10:05 am
by breeze4me
Fred wrote: Tue Apr 15, 2025 8:35 am
I fixed the crash when the DLL is dynamically loaded and auto-freed at end in 6.21 beta 5 (ie: CloseLibrary() not called). But if you close the DLL before exiting, there is still some callbacks registered from the DLL in the main process and it will crash because the window will try to call the callback when doing its cleanup. So you can either let the program unload the DLL automatically at end or close all the windows before calling CloseLibrary().
Thank you for the explanation.
