How does GDB informs remote stub about '^Cremote_interrupt called '

[Modi Banti]

I am building a remote stub for an Arm simulator. I am 
using sockets to communicate with GDB. when I want to 
break my program using through GDB( C -c) I cann see the 
message ' ^Cremote_interrupt called' in GDB but I dont get 
any packets in my reomte stub. I am not sure how GDB 
informs the remote target to stop? does anybody have any 
idea about this?