Software :: How To Debug Ns-2 Code For Segfault

Code:
$ cat segfault.c
int main(void)
{
char *s = "hello world";
*s = 'H';

[Code]....

So, now we know where exactly the problem occures. I know only these three commands to debug using gdb. But in case of ns-2 code, I don't know how to use gdb.

I changed a routing protocol's C++ code in ns-2 and successfully recompiled ns-2 but when I run any tcl script with that particular protocol, I get 'segmentation fault'. Now I want to trace what part of the code is causing this. I have tried using 'printf's at suspectable places. Is this possible to debug ns-2 code with gdb just like the segfault.c above? I am useing fedora 9.