gdb problem

[Bin Rong]

Hi there,

I encountered a problem when I was using gdb. I used CTRL+ALT+ESC to kill
a running gdb process, but later on, when I tried to use gdb again, I
found some strange problem like this:

GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...(no debugging symbols
found)
Using host libthread_db library "/lib/tls/libthread_db.so.1".

(gdb) run
Starting program: /home/brong/Desktop/simulation/adaptive/simulation
warning: Child process unexpectedly missing: No child processes

Program terminated with signal ?, Unknown signal.
The program no longer exists.
You can't do that without a process to debug.


But actually I can run the small program without gdb, anybody can give me
some hints to fix this problem.
Thanks in advance!

Best Regards
Bin Rong