client socket example with heartbeat

set port 9000
set sock ""

proc read_data {sock} {
	puts [read $sock]
	if {[chan eof $sock]} {
		puts "chan is eof"
		chan event $sock readable {}
		chan close $sock
	}
}

proc uniform {str} {
	global port
	set ::sock [socket localhost $port]
	chan configure $::sock -translation binary -buffering none -blocking no
	set msg "RCTL\nBEGIN\n${str}\nEND"
	chan event $::sock readable "read_data $::sock"
	chan puts $::sock $msg
}

uniform "some task"

set dead no

proc heartbeat {} {
	if {[catch {puts $::sock .}]} {
		set ::dead yes
	}
	after 1000 heartbeat
}

proc check_for_death {args} {
	if {$::dead eq "yes"} {
		puts "yeah,... we're dead."
	}
}

trace add variable dead write check_for_death

heartbeat