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Hi,

I have a problem to use a code compiled with Microsoft Visual Studio 2022.
Basically the code generates a dll that takes an argument and returns another to an Excel cell. The code below works correctly in the 32-bit architecture of Office (generating code like Win32), but gives an error when receiving the variable "a" in the 64-bit version of Office.

double __stdcall fA(double& a) // causes an exception reading "a" - only in 64 bits mode
{
return a;
}

If I change the code to:
double __stdcall fA(double& a) // caues an exception reading "a" - only in 64 bits mode
{
return 5;
}
the number 5 is displayed correctly in corresponding Excel cell.

At the VBA module…
Declare PtrSafe Function fA Lib "C:\mydll.dll" (ByRef a As Double) As Double

Does anyone have any idea what this problem could be or the root cause of it?

C++
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What I have tried:

Hi,

I have a problem to use a code compiled with Microsoft Visual Studio 2022.
Basically the code generates a dll that takes an argument and returns another to an Excel cell. The code below works correctly in the 32-bit architecture of Office (generating code like Win32), but gives an error when receiving the variable "a" in the 64-bit version of Office.

double __stdcall fA(double& a) // caues an exception reading "a" - only in 64 bits mode
{
return a;
}

If I change the code to:
double __stdcall fA(double& a) // caues an exception reading "a" - only in 64 bits mode
{
return 5;
}
the number 5 is displayed correctly in corresponding Excel cell.

At the VBA module…
Declare PtrSafe Function fA Lib "C:\mydll.dll" (ByRef a As Double) As Double

Does anyone have any idea what this problem could be or the root cause of it?

C++
Posted
Updated 12-Jan-23 6:26am
Comments
Richard MacCutchan 12-Jan-23 10:49am    
Are you trying to use the 32-bit dll with the 64-bit Office?
Danilo Lemos 2021 12-Jan-23 11:32am    
Yes but it doesn't work. When I compile the code in x86 mode it works only in 32 bits version.

1 solution

Quote:
Yes but it doesn't work. When I compile the code in x86 mode it works only in 32 bits version

Well, that's why it doesn't work.

You cannot combine 32 and 64-bit code in the same process. If you're using 64-bit Office, the .DLL you're using must also be compiled 64-bit. The same goes for 32-bit Office. If you're using 32-bit Office, the .DLL must be compiled 32-bit.

This goes for ALL applications in Windows, not just Office.
 
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