Regarding writing to /proc entries

[ravi]

Hi,
The README file in /sys/fs/procfs directory says that we can send the
control messages to note or ctl files for any process . But when we
execute the command 

	echo hup > /proc/curproc/note

		OR
	echo attach > /proc/2/ctl

the following error message comes on the terminal .

$ echo hup > /proc/curproc/note
/proc/curproc/note: Operation not supported

and 

$ echo attach > /proc/2/ctl
/proc/2/ctl: Operation not supported



What is the reason for this ?

Is it not possible to write the control words or control messages to the
process entries under /proc ?

Please reply to this mail .

Regards,
N Ravi