[php] exec "stty -F /dev/ttyUSB0 -hupcl" not work

Forum 2005-2010 (read only) Hardware Interfacing
1

I would disable DTR (in order to prevent Arduino 10k autoreset) through a PHP code inserted into phpclasses.

The shell code to disable DTR (hupcl in *X style) is

stty -F /dev/ttyUSB0 -hupcl

so I wrote:

exec("stty -F /dev/ttyUSB0 -hupcl");

but it doesn't work

Apache error log doesn't report any error so the command is issued but don't take any effect.

Was wondering where I'm mistaking and how I can add the above command to get the desidered behaviuor.

Thanks in advance.