a part of [stdio], this ''file'' is opened by default for each application making use of the stdio package of code. 

This input file may correspond to a disk file, pipe, terminal device, or other construct.

To refer to the stdin filehandle in Tcl, use the string '''stdin''' 
when using [gets] .

A quite distinct use of the same word refers to the stdin
[package] [Stephen Uhler] includes with [tclhttpd].
----
An example of reassigning stdin and providing a prompt
and capturing user input for tclsh.

 #!/usr/bin/tclsh
 # by Mike Tuxford
 #
 # the handler for stdin
 proc localHandler {} {
   # get the data from stdin
   gets stdin data
   # client will exit if you type "exit". How original!
   if {$data == "exit"} {
     exit
   } else {
     # process your data here, or pass it to another proc
     # or pass it to a local/remote server

     # return a new pseudo-prompt
     puts -nonewline stdout \
       "[clock format [clock seconds] -format "%H:%M:%S"] Tcl> "
     flush stdout
   }
   return
 }
 # assign our event handler for stdin
 fileevent stdin readable localHandler
 # send a startup message and initial prompt
 puts -nonewline stdout \
   "Tcl pseudo-prompt activated... \
   \n[clock format [clock seconds] -format "%H:%M:%S"] Tcl> "
 flush stdout
 # enter the tcl event loop
 vwait __forever__

[Mike Tuxford]

----

You can even use it with inetd for an instant TCP/IP server:

in your services file:
 test 10000/tcp

in your /etc/inetd.conf:
 test stream tcp /home/user/develop/program.tcl program.tcl

Then in your program just read stdin like above and that's it!

[JC]

----
[SB]: Turn off buffering on stdout to use repetitive -nonewline in interactive input with tclsh:

 fconfigure stdout -buffering none
 puts -nonewline "Give me your input: "
 gets stdin first
 puts -nonewline "Give me another input: "
 gets stdin second
 puts "First you told me $first and then $second"

----
[Category Glossary]