_U_DYN_CANCEL(3libunwind)

💖 _U_DYN_CANCEL — cancel unwind-info for dynamically generated code 💖

okay bestie, welcome to the libunwind corner of the manual pages (it's 3libunwind, iykyk) and today we're talking about _U_dyn_cancel 🎀

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✨ NAME ✨

_U_dyn_cancel — cancel unwind-info for dynamically generated code 🦋

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🌸 SYNOPSIS 🌸

#include <libunwind.h>

void _U_dyn_cancel(unw_dyn_info_t *di);

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💅 DESCRIPTION 💅

So like, the _U_dyn_cancel() routine cancels the registration of the unwind info for a dynamically generated procedure. That's the whole vibe. You're telling libunwind "bestie, we're done here, take it off the books" 💀

The argument di is the pointer to the unw_dyn_info_t structure that describes the procedure's unwind-info. That's your pointer, the one describing the thing, don't lose it 👑

And here's the iconic part: the _U_dyn_cancel() routine is guaranteed to execute in constant time — but only in the absence of contention from concurrent calls to _U_dyn_register() or _U_dyn_cancel(). No cap, that's the actual guarantee, and it's giving main character energy ⭐

🫶 fr fr, remember that little parenthetical: constant time only holds when nobody else is out here hammering _U_dyn_register() or _U_dyn_cancel() at the same time. Concurrent calls = contention = not the chill constant-time moment you wanted.

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🌈 THREAD AND SIGNAL SAFETY 🌈

• _U_dyn_cancel() is thread safe ✅
• but it is not safe to use from a signal handler 🙈

so go ahead and call it from your threads, just not from inside a signal handler, okay? that's the rule, periodt 💜

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🦋 SEE ALSO 🦋

• libunwind-dynamic(3libunwind)
• _U_dyn_register(3libunwind)

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👑 AUTHOR 👑

David Mosberger-Tang

• Email: dmosberger@gmail.com
• WWW: http://www.nongnu.org/libunwind/

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and that's the whole page bestie, no crumbs left 🍓 this lil slice of the Programming Library is dated 29 August 2023, and yes the original header said _U_DYN_CANCEL(3libunwind) and the footer said the same — consider yourself fully briefed 💖✨🎀🦋🌸