CODEWITHSUNDEEP
socketshttp-redirecttcl
Anand
Anand

Reputation: 1122

tcl/tk - Can we redirect the tcl stdout to a socket?

I am trying to redirect my stdout and stderr output to a text widget and I tried Memchan to do it and it did not work.

The next option we are looking at is using sockets. Can we redirect tcl stdout to a socket? If yes, can you provide an example code to demonstrate that?

Upvotes: 2

Views: 1053

Answers (2)

Bryan Oakley
Bryan Oakley

Reputation: 385910

What exactly do you mean by "redirect my stdout"? Do you mean, when you do a puts foo you want that to go to a socket? If so, simply replace the default puts command with your own which writes to the socket. You do that by renaming puts to something else, then creating your own proc named puts. Then, your proc will use the renamed command to do the actual I/O, but you can interject the socket as an argument.

Upvotes: 0

Donal Fellows
Donal Fellows

Reputation: 137567

Can you run in a subprocess? It's easy if you can:

socket -server accept 12345   ;# pick your own port number...
proc accept {channel host port} {
    exec [info nameofexecutable] realScript.tcl \
            <@$channel >@$channel 2>@$channel &
}
vwait forever                 ;# run the event loop to serve sockets...

This starts a Tcl subprocess executing realScript.tcl for each incoming socket connection, and arranges for stdin (<@) stdout (>@) and stderr (2>@) to be redirected to the socket. It also runs the subprocess in the background (final &) so that it doesn't block incoming connections. (You might want to check $host and $port for acceptability before running the subprocess.)

What's even better, in the subprocess Tcl will still auto-detect that it's dealing with sockets; the fconfigure command will be able to see the socket configuration (even if it can't change what port its talking to, of course).

Upvotes: 2

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