In Tcl, setting up TCP network connections is very simple. With a few lines of code a csound server can be built. This can accept connections from the local machine or from remote clients. Not only Tcl/Tk clients can send commands to it, but TCP connections can be made from other sofware, such as, for instance, Pure Data (PD). A Tcl script that can be run under the standard tclsh interpreter is shown below. It uses the Tclcsound module, a dynamic library that adds the Csound API commands to Tcl.
# load tclcsound.so #(OSX: tclcsound.dylib, Windows: tclcsound.dll) load tclcsound.so Tclcsound set forever 0 # This arranges for commands to be evaluated proc ChanEval { chan client } { if { [catch { set rtn [eval [gets $chan]]} err] } { puts "Error: $err" } else { puts $client $rtn flush $client } }
# this arranges for connections to be made
proc NewChan { chan host port } { puts "Csound server: connected to $host on port $port ($chan)" fileevent $chan readable [list ChanEval $chan $host] }
# this sets up a server to listen for # connections
set server [socket -server NewChan 40001] set sinfo [fconfigure $server -sockname] puts "Csound server: ready for connections on port [lindex $sinfo 2]" vwait forever
With the server running, it is then possible to set up clients to control the Csound server. Such clients can be run from standard Tcl/Tk interpreters, as they do not evaluate the Csound commands themselves. Here is an example of client connections to a Csound server, using Tcl:
# connect to server set sock [socket localhost 40001] # compile Csound code puts $sock "csCompile -odac orchestra score" flush $sock
# start performance puts $sock "csPlay" flush $sock
# stop performance puts $sock "csStop" flush $sock
As mentioned before, it is possible to set up clients using other software systems, such as PD. Such clients need only to connect to the server (using a netsend object) and send messages to it. The first item of each message is taken to be a command. Further items can optionally be added to it as arguments to that command.