Call Delphi DLL from C++\CLI with many parameters

Question

I have Delphi 2010 built DLL with two methods:

function Foo1(a, b: Integer):PChar; export; stdcall;
function Foo2(a, b, c:Integer):PChar; export; stdcall;

exports Foo1, Foo2;

Each of them returns Result := PChar('Test') .

My C++\CLI code

in header

typedef const wchar_t* (*pFUNC1)(int a, int b);
pFUNC1 TestFoo1;

typedef const wchar_t* (*pFUNC2)(int a, int b, int c);
pFUNC2 TestFoo2;

Initialize by LoadLibrary and GetProcAddress functions. Usage: TestFoo1(0,0) and TestFoo2(0,0,0);

Both works in Release mode.
But in Debug mode Foo2 is being aborted.

Please advise what is wrong.

Answer 1

Most likely you have calling convention mismatch. Change the stdcall in the Delphi to cdecl to match your C++/CLI code.

As an aside, you will need to be careful with the lifetime of your strings if ever you attempt to return a value from the DLL that is not a literal stored in read-only memory in the data segment. But that's not the problem here because PChar('Test') has the same lifetime as the DLL.