THR_WAKE(2)

🎀 THR_WAKE(2) 🎀

okay bestie, this is THR_WAKE(2) from the System Calls Manual, and it's giving tiny but important threading syscall energy. Let's get into it. 💅

✨ NAME ✨

thr_wake — wake up the suspended thread. 🫶

💖 LIBRARY 💖

Standard C Library (libc, -lc). yes, that's the one. ✨

🦋 SYNOPSIS 🦋

#include <sys/thr.h>

int
thr_wake(long id);

🌸 DESCRIPTION 🌸

Okay so first things first: this function is intended for implementing threading. Normal applications should use pthread_cond_timedwait(3) together with pthread_cond_broadcast(3) for typical safe suspension with cooperation of the thread being suspended, or pthread_suspend_np(3) and pthread_resume_np(3) in some specific situations, instead. That's the recommended path, bestie — thr_wake() is more of an internal-tooling moment. 🙈

Here's the tea. Passing the thread identifier of the calling thread (see thr_self(2)) to thr_wake() sets a thread's flag to cause the next signal-interruptible sleep of that thread in the kernel to fail immediately with the EINTR error. The flag is cleared by an interruptible sleep attempt or by a call to thr_suspend(2). This is used by the system threading library to implement cancellation. periodt. ✅

If id is not equal to the current thread identifier, the specified thread is woken up if suspended by the thr_suspend(2) system call. If the thread is not suspended at the time of the thr_wake call, the wake is remembered and the next attempt of the thread to suspend itself with the thr_suspend(2) results in immediate return with success. Only one wake is remembered. no stacking, no hoarding — just one lil wake note. 📝

💜 RETURN VALUES 💜

The thr_wake() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. simple as that. 😌

🔥 ERRORS 🔥

The thr_wake() operation returns these errors:

• [ESRCH] — The specified thread was not found or does not belong to the process of the calling thread. 💀

🌈 SEE ALSO 🌈

ps(1), thr_self(2), thr_suspend(2), pthread_cancel(3), pthread_resume_np(3), pthread_suspend_np(3)

👑 STANDARDS 👑

The thr_suspend() system call is non-standard and is used by 1:1 Threading Library (libthr, -lthr) to implement IEEE Std 1003.1-2001 (“POSIX.1”) pthread(3) functionality. so yeah, non-standard icon behavior — keep that in mind. 🧚

🕰️ HISTORY 🕰️

The thr_suspend() system call first appeared in FreeBSD 5.2. iconic since day one, fr fr. ⭐

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That's the whole page, bestie. xoxo from your Debian girlie 💅 — this one is dated May 5, 2020, and it's the THR_WAKE(2) manual page. 🎀