Issue on function pointers

[bustrus]

Hi there,

I'm trying to use a function pointer in a VCL app in Borland C++ Builder 5.0, but it won't work. I already tried it in a Console app, and it runs perfectly, but using it in VCL doesn't (probably the issue is related to static-non static members, but that's just an idea)

Here's what i did..

//in .h of class TfrmplgXMLstuff, 'private' section, the
//following:

void Check(CXml::Iterator& it);
void (*Delegate)(CXml::Iterator& it);

//in constructor of the form class (.cpp), the following:
//(already tried without &, without the class
//reference 'TfrmplgXMLstuff::', and a long etc of variants)

Delegate = &TfrmplgXMLstuff::Check;

//implementing Funct in .cpp
void TfrmplgXMLstuff::Check(CXml::Iterator& it)
{
// function code
}


The issue is that the compiler marks the assignation line in the contructor (Delegate = &TfrmplgXMLstuff::Check as error, and specifies:

[C++ Error] DlgplgXMLstuff.cpp(25): E2034 Cannot convert 'void (TfrmplgXMLstuff::*)(CTree<CXml::CXmlNode,const char *>::iterator &)' to 'void (*)(CTree<CXml::CXmlNode,const char *>::iterator &)'.

Since i used the exac same syntax in a console app, and it worked all right, i can't come up with any new idea...

would any one help?

Thx

B

 

[Prattaratt]

Look up Closure in the help index. You cannot assign a function pointer that points to a member function directly to a variable in BCB, but they implemented something called a closure signature that allows you to do so. I just don;t remember all the details.

 

[bustrus]

I went through all that before asking in the forum, and didn't work. The only thing they specify is that i should write explicitly in the code the reference to the class (since i'm working with non-static member functions), that is, ClassName::, in the declaration of the function and the function pointer, and later to make the assignation of the pointer into the function. I have also tried that (even though both my function and my function pointer are members of the same class, and i thought it might be redondant semanticly speaking).
If you (or anyone else) come up with any ideas, i'd appreciate it.

thnx & cheers

B.