Re: [Vegastrike-devel] Latest CVS segfaults

[Brian L. <bll...@ea...>]

On Wed, 2005-08-24 at 21:29 -0700, Daniel Horn wrote:
> for the record
> dynamic_cast only throws a std::bad_cast if you've tried to cast a
> reference...

Now, can anyone tell me why we do not use dynamic_cast, since we are
using pointers and not references?  It seems to be the correct item
right now.  If we are downcasting, I see no reason to put a cast at all,
and that is the only thing that I've seen being done, after reviewing
the code.  I didn't mean to get such a shouting match started over this.

Here is the last code from me on this.  It compiles just find under g++.


#include <string>
#include <iostream>

class a
{
public:
a() {};
virtual ~a() {};
};

class b: public a
{
public:
b() {};
virtual ~b() {};
};

class c
{
public:
c() {};
virtual ~c() {};
};


int main(int, char**)
{
a o1;
b o2;
a& or1 = o1;
a& or2 = o2;
a* op1 = &o1;
a* op2 = &o2;

try
{
std::cout << "TEST 1 dynamic_casting from a* to c* ";
c* t1 = dynamic_cast<c*>(op2);
if (t1==NULL)
std::cout << "NULL RETURNED\n";
else
std::cout << "We are goint to crash later\n";
}
catch (...)
{
std::cout << "EXEPTION THROWN\n";
}

void *t2=NULL;
try
{
std::cout << "TEST 2 dynamic_casting from a* to void* ";
t2 = dynamic_cast<void*>(op2);
if (t2==NULL)
std::cout << "NULL RETURNED\n";
else
std::cout << "We are goint to crash later if not careful\n";
}
catch (...)
{
std::cout << "EXEPTION THROWN\n";
}
#if 0 // won't compile
try
{
std::cout << "TEST 3 dynamic_casting from void* to a* ";
a* t3 = dynamic_cast<void*>(t2);
if (t3==NULL)
std::cout << "NULL RETURNED\n";
else
std::cout << "We are goint to crash later if not careful\n";
}
catch (...)
{
std::cout << "EXEPTION THROWN\n";
}
try
{
std::cout << "TEST 4 dynamic_casting from void* (a*) to c* ";
c* t4 = dynamic_cast<void*>(t2);
if (t1==NULL)
std::cout << "NULL RETURNED\n";
else
std::cout << "We are goint to crash later\n";
}
catch (...)
{
std::cout << "EXEPTION THROWN\n";
}
#endif

try
{
std::cout << "TEST 5 dynamic_casting from a& to c& ";
c& t5 = dynamic_cast<c&>(or1);
std::cout << "We are goint to crash soon\n";
}
catch (...)
{
std::cout << "EXEPTION THROWN\n";
}
return 0;
}



Now, back to trying to figure out OGRE and if it will be useful...