qthread_syncvar_empty/fill(3)

💖 NAME 💖

ok so bestie, meet qthread_syncvar_empty and qthread_syncvar_fill — they're the duo that sets the given syncvar to either "empty" or "full". that's it. that's the whole job. 💅

and jsyk this is all from libqthread, the qthread_syncvar_empty/fill(3) page, so like. you're in the right place. 🫶

✨ SYNOPSIS ✨

#include <qthread.h>

int
qthread_syncvar_empty (syncvar_t *dest);

int
qthread_syncvar_fill (syncvar_t *dest);

🦋 DESCRIPTION 🦋

okay so here's the tea ☕ — qthread_syncvar_empty() and qthread_syncvar_fill() assert the empty or full state of the given dest addresses. like, they just declare it. manifesting, but for syncvars. ✨

and the key thing, bestie, the part that's giving no waiting around: they do not wait for the addresses to be in any particular state. not even a little. not even a millisecond of "hmm let me check again". they say what they say and they move on. periodt. 💅

💜 RETURN VALUE 💜

• On success, the full/empty bits are modified and 0 is returned. 🎀 slay.
• On error, a non-zero error code is returned. 😭 not slay.

🔥 ERRORS 🔥

• QTHREAD_TIMEOUT — could not obtain the lock on the syncvar_t's status bits. bestie this one can happen for so many reasons and honestly some of them are unhinged:
  • memory corruption 💀
  • an invalid syncvar 🙈
  • or even just absurdly excessive contention — and yeah, that last one is because it's protected by a naive spinlock rather than a fair spinlock. not me getting bodied by a spinlock's whole personality 😭

🌸 SEE ALSO 🌸

• qthread_syncvar_writeF(3)
• qthread_syncvar_writeEF(3)
• qthread_syncvar_readFF(3)
• qthread_syncvar_readFE(3)

libqthread · APRIL 2011 — okay that's the whole page bestie, mwah 💋 go forth and set those syncvars, you absolute icon 👑✨🌈