Tk_HandleEvent(3tk)

💅 Tk_HandleEvent — bestie's guide to the Tk Library Procedures page

okay so picture this: you're deep in Tk, the manual section 3tk, and you need somebody to actually run the event handlers for window system events. that's this page. hi. welcome. 🫶

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✨ NAME ✨

Tk_HandleEvent — invoke event handlers for window system events 🦋

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✨ SYNOPSIS ✨

#include <tk.h>

Tk_HandleEvent(eventPtr)

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✨ ARGUMENTS ✨

• XEvent *eventPtr (in) — pointer to the X event you want dispatched to the relevant handler(s). IMPORTANT bestie, do not skip this: all the unused fields of the structure have to be set to zero. like, genuinely. zero them out. it's important. 🙈

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✨ DESCRIPTION ✨

so Tk_HandleEvent is the lower-level girlie who deals with window events 💅. it gets called by Tcl_ServiceEvent (and indirectly by Tcl_DoOneEvent), plus in a few other spots inside Tk.

what does she do? she makes callbacks to any window event handlers — the ones created by calls to Tk_CreateEventHandler — that match eventPtr, and then she returns. that's it. that's the whole job. iconic behavior honestly.

and lowkey sometimes it's useful for an application to just bypass the Tk event queue entirely and call Tk_HandleEvent directly, instead of doing Tcl_QueueEvent followed by Tcl_ServiceEvent. just skipping the line, main character energy. 👑

this procedure may be invoked recursively. yes fr fr. for example, it is possible to invoke Tk_HandleEvent recursively from a handler that was itself called by Tk_HandleEvent. 🌀

and that recursion thing? it's actually useful in some modal situations — like when a notifier has been popped up and an application wants to sit there and wait for the user to click a button in the notifier before doing literally anything else. the way that just works. ✨

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✨ KEYWORDS ✨

callback, event, handler, window 🌸

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okay that's the whole page, no notes. this was the Tk_HandleEvent(3tk) page from the Tk Library Procedures manual, brought to you by Tk itself, filed under Tk_HandleEvent(3tk). mwah, go zero out those unused fields bestie 💖🎀