On Thu, 2007-10-04 at 11:10 -0700, [EMAIL PROTECTED] wrote:
> I am seeing the following, for GDB step into a function.
What function ?
> Somehow the
> debug information is not there and it shows me some other file.
> Please help with me with this.
> I have compiled with -g all the way.
>
> #0 0x42bb6e76 in virtual thunk to
> vhpiVssPortDeclC::vhpiGetValue(vhpiValueT*) () at util.hh:178
The "virtual thunk" or "adjuster thunk" is a piece of code that adjusts
the offset of a pointer or reference to an object. For example:
========================= Test.cpp ============================
class P {
public:
void pvf(int x) {this.x = x;}
private:
int x;
};
class R {
public:
void pvf(int x) {//do nothing}
};
class S : P, R {
public:
void pvf(int x) { this.x = x * 2;}
};
#include <stdlib.h>
int main(void)
{
S s;
S* ps = &s;
P* pp = ps;//A pointer to a S object is also a pointer to a P object
//By polymorphism the following call should be dispatched to the
//overriding version of pvf (i.e. x = x * 2). But this function
//expects a pointer to a S object (i.e. the "this" pointer), yet
//the function can be called on either a S object pointer, P
//object pointer or R object pointer due to multiple
//inheritance.
//which requires the adjuster thunk to technically changes the
//pointer from either a P pointer or R pointer to S pointer.
//The adjuster thunk is called first to change the offset and
//then the function is called.
pp->pvf(2);
return EXIT_SUCCESS;
}
=========================== End of Test.cpp ==========================
Stepping a couple of steps through the adjuster thunk should eventually
take you to the beginning of your function.
Cheers,
--
John V. Shahid <[EMAIL PROTECTED]>
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