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vwait(n) [osx man page]

vwait(n)						       Tcl Built-In Commands							  vwait(n)


vwait - Process events until a variable is written SYNOPSIS
vwait varName _________________________________________________________________ DESCRIPTION
This command enters the Tcl event loop to process events, blocking the application if no events are ready. It continues processing events until some event handler sets the value of variable varName. Once varName has been set, the vwait command will return as soon as the event handler that modified varName completes. varName must be globally scoped (either with a call to global for the varName, or with the full namespace path specification). In some cases the vwait command may not return immediately after varName is set. This can happen if the event handler that sets varName does not complete immediately. For example, if an event handler sets varName and then itself calls vwait to wait for a different variable, then it may not return for a long time. During this time the top-level vwait is blocked waiting for the event handler to complete, so it cannot return either. EXAMPLES
Run the event-loop continually until some event calls exit. (You can use any variable not mentioned elsewhere, but the name forever reminds you at a glance of the intent.) vwait forever Wait five seconds for a connection to a server socket, otherwise close the socket and continue running the script: # Initialise the state after 5000 set state timeout set server [socket -server accept 12345] proc accept {args} { global state connectionInfo set state accepted set connectionInfo $args } # Wait for something to happen vwait state # Clean up events that could have happened close $server after cancel set state timeout # Do something based on how the vwait finished... switch $state { timeout { puts "no connection on port 12345" } accepted { puts "connection: $connectionInfo" puts [lindex $connectionInfo 0] "Hello there!" } } SEE ALSO
global(n), update(n) KEYWORDS
event, variable, wait Tcl 8.0 vwait(n)

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set(n)							       Tcl Built-In Commands							    set(n)


set - Read and write variables SYNOPSIS
set varName ?value? _________________________________________________________________ DESCRIPTION
Returns the value of variable varName. If value is specified, then set the value of varName to value, creating a new variable if one doesn't already exist, and return its value. If varName contains an open parenthesis and ends with a close parenthesis, then it refers to an array element: the characters before the first open parenthesis are the name of the array, and the characters between the parentheses are the index within the array. Otherwise varName refers to a scalar variable. Normally, varName is unqualified (does not include the names of any containing namespaces), and the variable of that name in the current namespace is read or written. If varName includes names- pace qualifiers (in the array name if it refers to an array element), the variable in the specified namespace is read or written. If no procedure is active, then varName refers to a namespace variable (global variable if the current namespace is the global namespace). If a procedure is active, then varName refers to a parameter or local variable of the procedure unless the global command was invoked to declare varName to be global, or unless a variable command was invoked to declare varName to be a namespace variable. SEE ALSO
expr(n), proc(n), trace(n), unset(n) KEYWORDS
read, write, variable Tcl set(n)
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