TCL_CREATECLOSEHANDLER(3tcl)

💖 TCL_CREATECLOSEHANDLER 💖

okay bestie, so you're out here in the Tcl Library Procedures and you want to know what happens when a channel gets yeeted into the void. that's what Tcl_CreateCloseHandler and Tcl_DeleteCloseHandler are for. we're arranging callbacks for when channels are closed. it's giving cleanup crew energy. no cap.

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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 for which you wanna create or delete a close callback. like, which channel are we doing this to, bestie 💅
• Tcl_CloseProc *proc (in) — the procedure that gets called as the callback. the actual function. the main character 🫶
• void *clientData (in) — arbitrary one-word value to pass to proc. literally just vibes you hand over so your function knows what's up ✨

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👑 DESCRIPTION 👑

Tcl_CreateCloseHandler</p> arranges for proc to be called when channel is closed with Tcl_Close or Tcl_UnregisterChannel, or using the Tcl close command. so basically: channel goes bye, your function gets the notification. periodt.

proc should match the following prototype:

typedef void Tcl_CloseProc(
        void *clientData);

The clientData is the same as the value provided in the call to Tcl_CreateCloseHandler. yes, the exact same one — it's not a copy, it's not a remix, it's the same value, fr fr 🎀

Tcl_DeleteCloseHandler removes a close callback for channel. the proc and clientData identify which close callback to remove. and here's the tea: Tcl_DeleteCloseHandler does nothing if its proc and clientData arguments do not match the proc and clientData for a close handler for channel. like it just stands there. silently. no error, no drama, nothing 💀

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🌈 SEE ALSO 🌈

close(3tcl), Tcl_Close(3tcl), Tcl_UnregisterChannel(3tcl)

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⭐ KEYWORDS ⭐

callback, channel closing

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and that's the whole page, bestie 💜 this one's from the Tcl crew, version 7.5, dated 7.5 — Tcl_CreateCloseHandler(3tcl) and that's on periodt 💅✨