Class's Binary Representation

I think so - I know that structures and functions written in Pascal and built with Delphi can be accessed in C on Windows. Last year I wrote a plugin in C for an app written in Delphi. It took a bit of fussing to get the datatypes correct but I succeeded. Take a look at the sample plugins for PE Explorer - compare the Pascal source with the C source to get a sense of the differences and similarities between the two languages.

No.

For example, C strings are NULL-terminated, while Pascal strings hold the length of the string in their first byte. Therefore, you cannot pass a C string to a Pascal function, and conversely.

You have to use a framework like COM or CORBA that do the translation for you.

Documents [ GDNet | MSDN | STL | OpenGL | Formats | RTFM | Asking Smart Questions ]
C++ Stuff [ MinGW | Loki | SDL | Boost. | STLport | FLTK | ACCU Recommended Books ]

Thank you LessBread. Fruny, you have no idea what the question was. 1.Pascal CAN declare, manage and use null-terminated strings. 2.Delphi allows one to convert between the two with a simple typecast. 3.I had thought that the INTERFACE types were to declare abstract classes that don't derive from TObject in order to work outside of Delphi. They're actually to associate a GUID with an abstract class not derived from TObject. 4.What LessBread says agrees with my observation that calling a TObject derived class in C++ Builder as a non-TObject-derived one works. 5.When you pass an object to a function you NEVER pass the actual object, only a pointer to it.

void Signature(void* Pointer)
{
PObject(Pointer)->ShowMessage("Why do we need so many pointers?");
};


[edited by - Eli Gottlieb on June 18, 2002 7:34:49 PM]

Well, Fruny had me convinced! Actually, I started to reply by posting both the Pascal code and the C code for the PEX sample plugin and asking Fruny to explain how it was that the C based plugin worked also. Then I took a look at PEX with the Dependency Walker and saw that it imported OLEAUT32.DLL and made calls to various COM related string manipulation functions - SysAllocStringLen, SysFreeString among others - at which point I figured Fruny was correct so I let it ride. I usually keep in fairly close contact with the PEX authors but my last email to them has gone unanswered for nearly a week now - otherwise, I would fire off a question to them and find out for certain.

quote:

---

Original post by Eli Gottlieb
Thank you LessBread. Fruny, you have no idea what the question was.

---

Why do you think Delphi (even back in version 4, which I own) provides a facility to create a COM type library. Why do you think MS made such a big deal of touting the cross-language compatibility of its .NET platform.

"There is no joy greater than soaring high on the wings of your dreams, except maybe the joy of watching a dreamer who has nowhere to land but in the ocean of reality."

Documents [ GDNet | MSDN | STL | OpenGL | Formats | RTFM | Asking Smart Questions ]
C++ Stuff [ MinGW | Loki | SDL | Boost. | STLport | FLTK | ACCU Recommended Books ]

quote:

---

Original post by Fruny
No.

For example, C strings are NULL-terminated, while Pascal strings hold the length of the string in their first byte. Therefore, you cannot pass a C string to a Pascal function, and conversely.

You have to use a framework like COM or CORBA that do the translation for you.

---

Oh common, it took me all of 2 minutes and 12second to write a ShortString class in C++ that perfectly emulates Delphi''s shortstring struct.

It''s also completely possible to vector to Delphi __fastcall''s from MSVC (unlike what is plastered all over the web by API dweebs). That took me all of 30minutes to reverse engineer - they use a very logical pattern, and after the first three, I didn''t need to disassemble any more example Delphi code to figure out how the parameters are passed.

Now, if I had had the choice[i] I _would_ have used COM - but it''s not like it''s impossible to make C++ talk Delphi''s language.
It''s not transparent, nor easily maintainable, but it is possible.