PTHREAD_SCHEDPARAM(3)

💅 PTHREAD_SCHEDPARAM(3) — thread scheduling parameter manipulation, bestie edition

okay so this is a page from the Library Functions Manual and honestly? it's giving "let me control exactly how your thread gets its turn on the CPU." We're talking pthread_setschedparam and pthread_getschedparam — the setter and the getter. iconic duo, no cap 🎀

---

📚 LIBRARY

POSIX Threads Library — that's libpthread, and you link it with -lpthread. periodt.

---

✨ SYNOPSIS ✨

#include <pthread.h>

int
pthread_setschedparam(pthread_t thread, int policy,
    const struct sched_param *param);

int
pthread_getschedparam(pthread_t thread, int *restrict policy,
    struct sched_param *restrict param);

---

🦋 DESCRIPTION 🦋

So pthread_setschedparam() and pthread_getschedparam() set and get the scheduling parameters of individual threads. Like, per-thread vibes. Not the whole process, bestie — one thread at a time 💅

The scheduling policy for a thread can be one of these three:

• SCHED_FIFO — first in, first out 🌈
• SCHED_RR — round-robin 🎀
• SCHED_OTHER — timesharing ⭐

And the valid thread priorities — those you access via param->sched_priority — have to be within the range returned by the sched_get_priority_min(2) and sched_get_priority_max(2) system calls. That's the range, okay? don't go outside it 🙈

---

🫶 RETURN VALUES 🫶

If everything's slaying, these functions return 0. Otherwise an error number comes back to tell you what went wrong. that's it, that's the whole thing.

---

💀 ERRORS 💀

So pthread_setschedparam() will fail if:

• [EINVAL] — invalid value for policy. (you gave it a policy that isn't a policy, bestie 😭)
• [ENOTSUP] — invalid value for scheduling parameters.
• [EPERM] — the calling thread does not have sufficient privilege to perform the operation. (no permission, no party 🔥)
• [ESRCH] — non-existent thread thread.

And pthread_getschedparam() will fail if:

• [ESRCH] — non-existent thread thread. (same energy, thread literally not found)

---

👑 SEE ALSO 👑

• sched_get_priority_max(2)
• sched_get_priority_min(2)

---

🌸 STANDARDS 🌸

The pthread_setschedparam() and pthread_getschedparam() functions conform to Version 2 of the Single UNIX Specification (“SUSv2”). certified official, iykyk ✨

---

ngl the whole thing is a two-function page and it still ate. read the min/max priority calls before you go setting anything, fr fr 🧚

---

mwah 💜 this page came from Debian, dated October 17, 2022 — and that's the whole manual page, bestie, see you in the next one 🎀