PTHREAD_RWLOCK_UNLOCK(3)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

💅 PTHREAD_RWLOCK_UNLOCK(3) — like, the read/write lock release era 🎀

Okay bestie, so this one's from the Library Functions Manual (POSIX threads girlies, stand up), and it's literally the "let it go" of the pthread world. Buckle in. ✨

🌸 NAME 🌸

pthread_rwlock_unlock — release a read/write lock. That's it, that's the whole vibe. You grabbed a lock, now you're putting it back. Iconic behavior. 💖

🦋 LIBRARY 🦋

POSIX Threads Library, aka libpthread, aka -lpthread. Link her and she slays. 🔥

✨ SYNOPSIS ✨

#include <pthread.h>

int
pthread_rwlock_unlock(pthread_rwlock_t *lock);

Yes, that's the whole signature. Short. Sweet. Main character energy. 💅

👑 DESCRIPTION 👑

So, pthread_rwlock_unlock() is the function you call to release the read/write lock that you previously snagged with pthread_rwlock_rdlock(), pthread_rwlock_wrlock(), pthread_rwlock_tryrdlock(), or pthread_rwlock_trywrlock(). 🫶

Like, no cap — it's the cleanup crew. You got the lock through any of those four paths, this is the one that hands it back. All four roads lead to the same unlock. Periodt. ⭐

🎀 RETURN VALUES 🎀

If everything's gucci, pthread_rwlock_unlock() returns zero. 🥳

Otherwise, it'll hand you back an error number to let you know something went sideways. Not the vibe, but okay. 😭

⚠️ Okay so this part is important, bestie: the results are undefined if lock is not held by the calling thread. Like, undefined. As in, don't do it. Not a drill. 💀

💜 ERRORS 💜

pthread_rwlock_unlock() may fail if:

  • [EINVAL] — the value specified by lock is invalid. It's giving "that's not a real lock, girl." 🙈
  • [EPERM] — the current thread does not own the read/write lock. You're trying to unlock something that isn't yours. Not your lock, not your problem, and also an error. 😤

🌈 SEE ALSO 🌈

🧚 STANDARDS 🧚

pthread_rwlock_unlock() is expected to conform to Version 2 of the Single UNIX Specification (that's “SUSv2” to the friends it doesn't have). Lowkey a legend. 👑

🍓 HISTORY 🍓

The pthread_rwlock_unlock() function first appeared in FreeBSD 3.0. Ancient in tech years, still serving. ⭐

Alright, that's the whole page, bestie — go forth and unlock responsibly. 💅✨

Signed, sealed, delivered: this little love letter lives in the Debian edition of the manual, dated August 4, 1998 — yes, she's a 90s baby and she ate. 🎀🔥

📦 where this page comes from