Tcl_CreateCloseHandler(3)

✨ Tcl_CreateCloseHandler ✨

okay bestie, we're looking at the Tcl Library Procedures page for Tcl_CreateCloseHandler and Tcl_DeleteCloseHandler — it's giving "set up callbacks for when channels get closed" and honestly? iconic. 💅

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🌸 NAME 🌸

Tcl_CreateCloseHandler, Tcl_DeleteCloseHandler — arrange for callbacks when channels are closed 🎀

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🦋 SYNOPSIS 🦋

#include <tcl.h>

Tcl_CreateCloseHandler(channel, proc, clientData)

Tcl_DeleteCloseHandler(channel, proc, clientData)

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💖 ARGUMENTS 💖

• Tcl_Channel channel (in) — the channel you wanna create or delete a close callback for, no cap 🫶
• Tcl_CloseProc *proc (in) — the procedure that gets called as the callback, literally the whole point ✨
• void *clientData (in) — an arbitrary one-word value you pass along to proc 🎀

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👑 DESCRIPTION 👑

so here's the tea, bestie: Tcl_CreateCloseHandler arranges for proc to be called when channel is closed — and we mean closed with Tcl_Close or Tcl_UnregisterChannel, or by using the Tcl close command. 🌈

Your proc should match this prototype, exactly, character for character:

typedef void Tcl_CloseProc(
        void *clientData);

the clientData you get in there is the same value you handed over in the call to Tcl_CreateCloseHandler. same one, fr fr. 💜

Tcl_DeleteCloseHandler removes a close callback for channel. the proc and clientData together are what identify which close callback to remove — that's the vibe check that decides who gets yeeted. 🙈

⚠️ heads up: Tcl_DeleteCloseHandler does nothing if its proc and clientData arguments do not match the proc and clientData for a close handler for channel. like, nothing nothing. it just stands there. 💀

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🔥 SEE ALSO 🔥

• close(n)
• Tcl_Close(3)
• Tcl_UnregisterChannel(3)

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⭐ KEYWORDS ⭐

callback, channel closing

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and that's the whole page, bestie — go forth and handle those closes 💅

this one's from the Tcl library docs, version 7.5, and the date stamp is 7.5 too, so yeah, it's been around a minute and it still ate. periodt. 🎀💖✨