zstd_flush_stream(9)

📦 version 7.3.1, in nixpkgs unstable

💅 zstd_flush_stream(9) — from the Kernel API Manual ✨

okay bestie, so we're in the kernel docs, section 9, and today's main character is zstd_flush_stream. she's a lil function with a big job and honestly? she ate. let's get into it 🎀

✨ NAME ✨

zstd_flush_stream — flush internal buffers into output 💖

Like, literally what it says on the tin. the internal buffers? they're getting emptied. into the output. periodt.

🌸 SYNOPSIS 🌸

size_t zstd_flush_stream (zstd_cstream *cstream , zstd_out_buffer
*output );

no cap, that's the signature. keep it exactly like that, the compiler is not as forgiving as your group chat 😭

🦋 ARGUMENTS 🦋

  • cstream — the zstd streaming compression context. she's the whole vibe, your state, your everything 💅
  • output — the destination buffer. and here's the important bit, output->pos gets updated to indicate how much compressed data was written. so like, don't go reading pos before you call it, that's giving chaos 🌈

👑 DESCRIPTION 👑

okay so zstd_flush_stream must be called until it returns 0, because that's the signal meaning all the data has been flushed. like, fully drained. zero means we're done, bestie ✨

but here's the tea ☕ — zstd_flush_stream causes a block to be ended. so if you're calling it too often? that will degrade the compression ratio. ngl, it's giving "using a firehose to water one plant" 💀 be chill about it.

🫶 real talk: keep calling it until you get 0, but don't spam it for no reason. two different rules, both matter. iykyk.

🍓 RETURN 🍓

it returns the number of bytes still present within internal buffers, or an error 🔥

and how do you know if it's an error? you can check it using zstd_is_error. that's the vibe check function, use it 🙈

💜 SEE ALSO 💜

the kernel file ./include/linux/zstd.h and, like, the entire extended friend group:

like, the whole squad. go read them, they're iconic too 💅✨

and that's the page, bestie 🧚 source lives in ./include/linux, dated October 2026, and the page itself is zstd_flush_stream(9) — mwah, love that for us 💖🎀🦋

📦 where this page comes from