QB_ATOMIC_...D_EXCHANGE(3)

💖 QB_ATOMIC_...D_EXCHANGE(3) 💖

okay bestie, so this one lives in the libqb Programmer's Manual and honestly? it's giving "tiny function, enormous power." her whole name is qb_atomic_int_compare_and_exchange and she's about to become your new hyperfixation. no cap. 🦋

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✨ NAME ✨

qb_atomic_int_compare_and_exchange — compares oldval with the integer pointed to by atomic and, if they're equal, atomically exchanges *atomic with newval. 💅

like... she checks if you're the same person, and if you are, she swaps you out. iconic behaviour honestly.

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🌸 SYNOPSIS 🌸

#include <qb/qbatomic.h>

int32_t qb_atomic_int_compare_and_exchange(
    volatile int32_t QB_GNUC_MAY_ALIAS   *atomic,  /* a pointer to an integer */
    int32_t                               oldval,  /* the assumed old value of *atomic */
    int32_t                               newval   /* the new value of *atomic*/
);

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🎀 PARAMS 🎀

• atomic — a pointer to an integer. she's the one getting compared and possibly swapped. main character energy fr fr. 👑
• oldval — the assumed old value of *atomic. you're basically guessing "i think she's currently this." 🫶
• newval — the new value of *atomic. the glow-up you're giving her if the vibe check passes. ✨

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💀 DESCRIPTION 💀

Also acts as a memory barrier.

that's it, that's the description, but bestie do not sleep on that sentence — it's the whole point. she's not just comparing numbers, she's putting a whole fence in the memory ordering. it's giving bouncer at the club. 🚧

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⭐ RETURN VALUE ⭐

• QB_TRUE — if *atomic was equal oldval. she said yes. slay. 🎉
• QB_FALSE — otherwise. she said no. not me getting rejected by an atomic operation 😭

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🔥 SEE ALSO 🔥

the whole friend group, because she does not work alone:

• qb_atomic_int_set(3)
• qb_atomic_int_get(3)
• qb_atomic_int_add(3)
• qb_atomic_init(3)
• qb_atomic_pointer_get(3)
• qb_atomic_int_exchange_and_add(3)
• qb_atomic_pointer_compare_and_exchange(3)
• qb_atomic_pointer_set(3)

go read them. iykyk. 🌈

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👑 COPYRIGHT 👑

Copyright (C) 2003 Sebastian Wilhelmi

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that's the whole page, bestie, and yes i know the title looks like it got cut off mid-sentence — it's literally QB_ATOMIC_...D_EXCHANGE(3), from libqb, dated 2025-09-16, and the footer says LIBQB too. mwah. 💖