UNW_SET...HE_SIZE(3libunwind)

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💖 UNW_SET_CACHE_SIZE — bestie edition 💖

okay so this is a page from the Programming Library manual, third section of libunwind (3libunwind), and today we're learning about unw_set_cache_size. sit down, get comfy, we're doing this 🫶

✨ NAME ✨

unw_set_cache_size — set the unwind cache size, that's literally it, that's the whole job 💅

🌸 SYNOPSIS 🌸

#include <libunwind.h>

int unw_set_cache_size(unw_addr_space_t as, size_t size, int flag);

🦋 DESCRIPTION 🦋

so the unw_set_cache_size() routine sets the cache size of the address space as so it can hold at least as many items as the number you pass in size. key word: at least. it might hold more items than you asked for, because that's up to the implementation, not you, bestie 🙈

and if you want to turn caching off entirely? call unw_set_caching_policy) with a policy of UNW_CACHE_NONE. yes, that's the move. no notes. ✨

oh and flag? it's currently unused and must be 0. not "should be", not "preferably", it must be 0. periodt. 👑

💜 RETURN VALUE 💜

when it works, unw_set_cache_size() returns 0. slay. 🎀

when it doesn't work, you get the negative value of one of the error codes listed below. so like, the bad vibes come with a minus sign. 💀

🔥 THREAD AND SIGNAL SAFETY 🔥

unw_set_cache_size() is thread-safe — go off, multi-threaded queens 👑

but it is not safe to use from a signal handler. do not do that. that's the vibe check it fails. 🚫

💀 ERRORS 💀

  • UNW_ENOMEM — the desired cache size could not be established because the application is out of memory. the cache simply said "i can't, i'm full" 😭

🌈 SEE ALSO 🌈

go read those next, iykyk 🧚

👑 AUTHOR 👑

Dave Watson

and that's the whole page, bestie, no cap, fr fr 💖 this was Programming Library business, dated 29 August 2023, filed under UNW_SET...HE_SIZE(3libunwind) — bye, love u, go set some cache sizes responsibly 🍓✨

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