Analysing the Core dump in Unix

Here I will explain the procedure to analyze the core dump using the dbx tool with a sample c program.
My C file is: test.c
>cc test.c --> gave me a.out
>./a/out -->Running this generated the core dump in the same location

My test.c file:
int myFunc(int *p);

int main (void)
{
int *p = 0; /* null pointer */
printf("Hello,World\n");
return myFunc (p);

}
int myFunc (int *p)
{
int y = *p;
return y+y;
}

Now I am using the dbx tool to analyze the core
> dbx a.out core
For information about new features see `help changes'
To remove this message, put `dbxenv suppress_startup_message 7.4' in your .dbxrc
Reading a.out
core file header read successfully
Reading ld.so.1
Reading libc.so.1
Reading libdl.so.1
Reading libc_psr.so.1
program terminated by signal SEGV (no mapping at the fault address)
Current function is a
14 int y = *p;
(dbx) where --> this displays the call stack of the current procedure and the parameters
=>[1] myFunc(p = (nil)), line 14 in "test.c"
[2] main(), line 7 in "test.c"
(dbx) list --> displays the current source code file
14 int y = *p;
15 return y+y;
16 }
(dbx) dump myFunc --> displays the values of variables in a function
p = (nil)
y = -39942352
(dbx) print p --> disaply the value of a variable or expression
p = (nil)
(dbx) quit --> exit from dbx command

Related :

1. Creating and analyzing core dumps - Covers multiple platforms.Good to start with
   
2. Core dump management on Solaris OS
3. Core dump analysis on HP UX
4. dbx man page
5. gdb and dbx debuggers in Unix

NOTE
The above program didn't crash on an AIX unix machine.May be it allows to access the 0X00 memory location.So what I think the kind of errors that are considered/handled might vary from unix OS to OS.Refer this link for an example of analyzing the core on AIX machine.