dispatch_after(3)

💖 dispatch_after(3) — the "do this later bestie" page 💖

okay so this is the manual for dispatch_after, from section 3 (library functions) of the Darwin manual. she's a libc / dispatch girlie and she is iconic ✨

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🌸 NAME 🌸

dispatch_after — schedule blocks for deferred execution 🕐

like… run this thing, but NOT right now. later. on purpose. 💅

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✨ SYNOPSIS ✨

#include <dispatch/dispatch.h>

void
dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
    void (^block)(void));

void
dispatch_after_f(dispatch_time_t when, dispatch_queue_t queue,
    void *context, void (*function)(void *));

two whole functions bestie, both yours 🫶

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🦋 DESCRIPTION 🦋

so dispatch_after() submits the block to the given queue at the time specified by the when parameter. that's it, that's the whole vibe. ⏰

the when parameter is a value created by dispatch_time() or dispatch_walltime(). you don't just make one up, okay, you get it from those two. no cap.

if you want a more detailed description about submitting blocks to queues, go see dispatch_async(3). she's the main character of that topic, this page is just her time-delayed cousin 🎀

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⚠️ CAVEATS ⚠️

listen up bestie, this part matters 💀

• Specifying DISPATCH_TIME_NOW as the when parameter is supported, but it is not as efficient as calling dispatch_async(). it works!! it's just lowkey doing the most for no reason 🙈
• The result of passing DISPATCH_TIME_FOREVER as the when parameter is undefined. not "it waits forever", not "it never runs" — undefined. do not pass go. do not collect $200. 🚫

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🧚 FUNDAMENTALS 🧚

the dispatch_after() function is a wrapper around dispatch_after_f(). that's the lore. one is the cute front, the other is the machinery underneath. iykyk 👑

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🔥 SEE ALSO 🔥

• dispatch(3)
• dispatch_async(3)
• dispatch_time(3)

go read those too, they're all part of the same friend group fr fr 💜

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mwah 💋 this page is from the Darwin manual, dated May 1, 2009. love that for her. stay scheduled, stay slay ✨🦋🌸