snd_pcm_hw_param_last(9)

📦 version 7.3.1, in nixpkgs unstable

💅 snd_pcm_hw_param_last(9) — the Kernel API Manual moment

okay so bestie, welcome to the snd_pcm_hw_param_last(9) page from the Kernel API Manual. this one is short and sweet and honestly kind of a baddie: it's the "gimme the biggest value you got" of the ALSA hw-params world. let's get into it 💖

✨ NAME ✨

snd_pcm_hw_param_last — refine the config space and hand you back the maximum value. no cap, that's the whole gig.

🎀 SYNOPSIS 🎀

int snd_pcm_hw_param_last (struct snd_pcm_substream *pcm , struct
snd_pcm_hw_params *params , snd_pcm_hw_param_t var , int *dir );

🦋 ARGUMENTS 🦋

four little besties walk into a function:

  • pcm — your PCM instance. the main character, obviously.
  • params — the hw_params instance. this is the vibe check zone we're about to narrow down.
  • var — the parameter you actually want to retrieve. pick your fighter.
  • dir — a pointer to the direction, which is -1, 0, or 1... or NULL, if you're feeling mysterious. 🙈

🌸 DESCRIPTION 🌸

so like, inside the configuration space that params defines, this function takes var and removes all the values that are < maximum. yep, all of them. gone. then it reduces the configuration space accordingly — it literally rewrites the space so the leftovers are what's left. it's giving "spring cleaning but make it interval math" ✨

basically: maximum stays, everything below it gets the boot. periodt.

🔥 RETURN 🔥

returns the maximum on success 💅 — or a negative error code on failure. so if you get a negative number back, that's your sign, bestie, something went sideways 😭

👑 SEE ALSO 👑

okay this is the long part and i need you to stay with me — the kernel file lives at ./sound/core/pcm_lib.c, and these are all the friends-of-friends you should also go read (iykyk):

like i said. a whole friend group. read them all, they're iconic 🫶

lowkey reminder: this one returns the maximum — if you wanted the minimum instead, that's a whole other function, and yes, snd_pcm_hw_param_first(9) is sitting right there in SEE ALSO being all smug about it 💀

that's the whole page, bestie! 🌈 this lil masterpiece comes from the ./sound/core source and is dated October 2026, filed under snd_pcm_hw_param_last(9). go forth and refine your config space ✨🎀💜

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