On Wed, Apr 04, 2007 at 04:40:42PM +0400, Alexander Bubnov wrote:
> 
> Breakpoint 1, main () at ttt.c:20
> 20          puts("START TEST");
> (gdb) n
> 0x080484dc in init_fallthru ()
> (gdb)
> Single stepping until exit from function init_fallthru,
> which has no line number information.

This is not a bug.  You stepped the debugger into a function in the C
runtime, which isn't compiled with debugging symbols, then asked for
the next line when you probably needed to ask for the next instruction
("stepi").

Generally setting breakpoints right at program entry or exit may not
work quite as you expect.  It would be better perhaps to set the
breakpoint right after the first puts.

As you note, gdb6 does this better.  It's extremely unlikely anyone will
change this behavior in gdb5.

Thor