gdb gets suspended during debugging

gdb gets suspended during debugging

[Craig Jeffree]

Hi everyone,

I've discovered that GDB will get suspended/backgrounded when debugging
if it produces a terminal height worth of the "Detaching after fork from
child process..." messages.

This only occurs the first time the terminal fills up and you can simply
'fg' the debugger back to the foreground and it will continue without
any problems.  You can also work around it by doing 'set height 0' in
gdb as this prevents it from prompting when the terminal fills up.

I couldn't find any bugs regarding this in the database, only an
unanswered message in a mailing list somewhere.  Has anyone else seen
this before?  It is a bug isn't it?  Is there a better fix/workaround so
that I can keep my value for height untouched and not have to 'fg' the
debugger?

I've seen this with gdb 6.2 and 6.3, I compiled the example below with
gcc 3.2.3 and it occurs with both bash and tcsh.  I've only tested it
under RHEL3 & 4.

To see it for yourselves run this in GDB:
#include <unistd.h>

int main()
{
    while(1)
    {
        if (!fork())
            exit(1);

        sleep(1);
    }
}


Cheers,
Craig.

Re: gdb gets suspended during debugging

[Daniel Jacobowitz]

On Mon, Sep 12, 2005 at 02:51:43PM +1000, Craig Jeffree wrote:
> Hi everyone,
> 
> I've discovered that GDB will get suspended/backgrounded when debugging
> if it produces a terminal height worth of the "Detaching after fork from
> child process..." messages.

This was reported a few months ago and is fixed in GDB CVS.

-- 
Daniel Jacobowitz
CodeSourcery, LLC