VB vs. C++

[Skywing]

Myndfyre, what are you talking about?

Code Select Expand


Dim x as String
Dim y as Long

y = StrPtr(x)


y is now the pointer to x, x has the contents of y.  It's like y = &x in C++.

Mitosis: I think you've confused your compilers.

Can you then do things like modify the contents of x through y like you can in C++, without having to resort to unwieldy calls to exported memcpy functions?

[CupHead]

Not really, you have to use CopyMemory calls if you want to modify it.   I think the best information regarding these pointers is here: http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/q199/8/24.asp&NoWebContent=1

[Arta]

Not really

QED. VB < C/C++.

[Skywing]

Not really, you have to use CopyMemory calls if you want to modify it.   I think the best information regarding these pointers is here: http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/q199/8/24.asp&NoWebContent=1

Then VB doesn't have true pointers as part of the language itself.  Using a kludge with dll exports written in some other language doesn't make it a VB language feature.

[CupHead]

Then VB doesn't have true pointers as part of the language itself.  Using a kludge with dll exports written in some other language doesn't make it a VB language feature.

Um...  So nothing done in VB is a VB language feature because VB wasn't written in VB?

QED. VB < C/C++.

Jesus Christ, what is it with you people?  I wasn't arguing that VB is better, just that most people don't know about these similar features and that VB isn't all that bad.

[Skywing]

Then VB doesn't have true pointers as part of the language itself.  Using a kludge with dll exports written in some other language doesn't make it a VB language feature.

Um...  So nothing done in VB is a VB language feature because VB wasn't written in VB?

No.  A "language feature" is something that is intrinsically provided by (or is integrated with) the compiler/interpreter/etc.  If you have to explicitly callout to code written in some other language, it's not a language feature.

[CupHead]

Even though everything in VB is a call to something written in a different language, if it's in the VB runtime, then it's a language feature because it's provided already?  I think that's what you're saying?

[j0k3r]

Yeah Mitosis, VB will highlight the line and IIRC will tell you the error.

[Banana fanna fo fanna]

Even though everything in VB is a call to something written in a different language, if it's in the VB runtime, then it's a language feature because it's provided already?  I think that's what you're saying?

A pointer is not simply an integer (or long) containing the memory address of a variable. It is a vehicle that you can use to pass-by-reference, automatically look up the contents of memory at a certain address, and change that memory, all while using a single operator.

[CupHead]

A pointer is simply an unsigned long containing the memory address of a variable.  That's it, nothing more.  How and what functions a compiler is able to apply to that pointer have nothing to do with the fact that the object is a pointer.  The dereference operator is not a pointer.  It cannot be called a pointer.  The address-of operator is not a pointer either.  Passing by reference is not a pointer.  This "vehicle" you speak of is called a programming language, not a pointer.

[MyndFyre]

Not really, you have to use CopyMemory calls if you want to modify it.   I think the best information regarding these pointers is here: http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/q199/8/24.asp&NoWebContent=1

Then VB doesn't have true pointers as part of the language itself.  Using a kludge with dll exports written in some other language doesn't make it a VB language feature.

This ^^ is exactly what I was talking about.

Pointer usage is NOT a language feature of VB as it is in C/++.

[CupHead]

However, with VB, IIRC, you don't actually use pointers - that is, there's no way to access the contents to which they point.  You can marshal your data to point to strings or objects because other languages (enabled with COM) require this; however, aside maybe from function callbacks, you don't actually use pointers.

Actually, what you said was that you can't access the contents of a pointer, which is incorrect, because you can access the contents through the original variable.  If you were talking about something else, you should have said so.

[Mitosis]

Yeah Mitosis, VB will highlight the line and IIRC will tell you the error.

Well then my compiler is screwed up then, when ever there is an error it does nothing.

[j0k3r]

I think you need to enable the error display in options somewhere (I'm speaking from VB6 I think... don't remember all too well). I remember having to enable something when I took the classes.

[Banana fanna fo fanna]

A pointer is simply an unsigned long containing the memory address of a variable.  That's it, nothing more.  How and what functions a compiler is able to apply to that pointer have nothing to do with the fact that the object is a pointer.  The dereference operator is not a pointer.  It cannot be called a pointer.  The address-of operator is not a pointer either.  Passing by reference is not a pointer.  This "vehicle" you speak of is called a programming language, not a pointer.

No, it isn't. It's a syntax construct.