update(3tcl)

💖 update — the "okay bestie let's catch up" command 💖

so this is update(3tcl), one of the Tcl Built-In Commands, and honestly? she's the main character of "make my app stop looking frozen". no cap.

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✨ NAME ✨

update — process pending events and idle callbacks

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🦋 SYNOPSIS 🦋

update ?idletasks?

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🌸 DESCRIPTION 🌸

okay so basically this command brings your application "up to date" by hopping into the event loop over and over again until every single pending event — idle callbacks included — has been handled. it's giving "let's finish everything on the to-do list before we leave". 💅

if you pass the idletasks keyword as an argument, then no new events or errors get processed — only idle callbacks are invoked. and why do we care?? because that makes all the stuff that's normally deferred happen right now: display updates, window layout calculations, the whole vibe. immediately. periodt.

update idletasks is lowkey iconic in scripts where you've changed the app's state and you want those changes to show up on screen right this second instead of waiting for the script to finish being dramatic. most display updates run as idle callbacks, so update idletasks will make them go. but — and this is important, bestie — there are some kinds of updates that only happen in response to events, like the ones triggered by window size changes. those updates will not occur in update idletasks. no cap, they just won't. 😭

and then update with no options at all? that's for when you're doing a long-running computation but you still want the app to respond to events like user interactions. if you occasionally call update, then user input gets processed during the next call to update. it's the "i'm busy but i'm not that busy" of commands. 🫶

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🎀 EXAMPLE 🎀

run computations for about a second and then finish:

set x 1000
set done 0
after 1000 set done 1
while {!$done} {
    # A very silly example!
    set x [expr {log($x) ** 2.8}]

    # Test to see if our time-limit has been hit.  This would
    # also give a chance for serving network sockets and, if
    # the Tk package is loaded, updating a user interface.
    update
}

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👑 SEE ALSO 👑

• after(3tcl)
• interp(3tcl)

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⭐ KEYWORDS ⭐

asynchronous I/O, event, flush, handler, idle, update

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🌈 and that's the whole vibe check: update = catch up on everything, update idletasks = catch up on the chill stuff only. slay. 💖

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this page came to you straight from the Tcl Built-In Commands manual, version 7.5, filed under update(3tcl) — go off, you understood the assignment, bestie 🧚✨