pthread_setschedprio(3)

✨ pthread_setschedprio ✨

okay bestie, so this one lives in the Library Functions Manual section 3 dance, and it's a lil pthread girlie 💅. Buckle up, she's short but she's mighty.

🫶 NAME

pthread_setschedprio — set the scheduling priority of a thread

📚 LIBRARY

POSIX threads library — link with libpthread, i.e. -lpthread 🧵

🎀 SYNOPSIS

#include <pthread.h>

int pthread_setschedprio(pthread_t thread, int prio);

💖 DESCRIPTION

so basically pthread_setschedprio() sets the scheduling priority of the thread thread to whatever value you slid into prio. that's it. that's the whole job. iconic behavior honestly 👑

and like — contrast moment — pthread_setschedparam(3) changes both the scheduling policy and the priority of a thread. this one? just the priority. one-track mind, and we respect it for that 🎯

🌈 RETURN VALUE

• on success she returns 0 — clean, no notes ✨
• on error she returns a nonzero error number 😭
• and fr fr important: if pthread_setschedprio() fails, the scheduling priority of thread is not changed. no half-finished chaos. she either does it or she doesn't 🫡

💀 ERRORS

• EINVAL — your prio is not valid for the scheduling policy of the specified thread. wrong vibe for that policy, bestie 🙈
• EPERM — the caller does not have appropriate privileges to set the specified priority. not your lane, not your priority 🚫
• ESRCH — no thread with the ID thread could be found. she's not here, ghosted 💀

also, POSIX.1 documents an ENOTSUP error ("attempt was made to set the priority to an unsupported value") for pthread_setschedparam(3) — yes, for that one, not this one. just so you know 👀

🦋 ATTRIBUTES

for an explanation of the terms used in this section, go peek at attributes(7).

• Interface: pthread_setschedprio() — Attribute: Thread safety — Value: MT-Safe 🔥

⭐ STANDARDS

POSIX.1-2008. certified, no cap 📜

🌸 HISTORY

• glibc 2.3.4 — that's when she debuted 🎬
• POSIX.1-2001 — that's where she's from originally 📖

🧚 NOTES

want the tea on what permissions you need to change a thread's scheduling priority, what the actual effect of changing it is, and the permitted ranges for priorities in each scheduling policy? that's all over in sched(7). go read her, she ate 💜

👑 SEE ALSO

getrlimit(2), sched_get_priority_min(2), pthread_attr_init(3), pthread_attr_setinheritsched(3), pthread_attr_setschedparam(3), pthread_attr_setschedpolicy(3), pthread_create(3), pthread_self(3), pthread_setschedparam(3), pthreads(7), sched(7)

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ok that's the whole page, mwah 💋 this one's from Linux man-pages 6.20, dated 2025-09-21, and it's the pthread_setschedprio(3) page — go set some priorities bestie, you got this 🎀✨