hvc_iucv_queue(9)

📦 version 7.3.1, in nixpkgs unstable

👑 hvc_iucv_queue — the kernel API manual, but make it cute 🎀

okay bestie, so this one's from the Kernel API Manual section (hvc_iucv_queue(9) — that's the section 9 one, kernel internals, iykyk) and it's literally about buffering terminal data so it can go out later. very "just put it in the queue and trust the process" energy fr fr 💅

✨ NAME ✨

hvc_iucv_queue — buffer terminal data for sending. that's it, that's the whole vibe 🦋

🌸 SYNOPSIS 🌸

ssize_t hvc_iucv_queue (struct hvc_iucv_private *priv , const u8 *buf ,
size_t count );

look at her. three args, one return type, zero drama. icon behavior honestly ⭐

💖 ARGUMENTS 💖

  • priv — a pointer to a struct hvc_iucv_private instance. like, the specific private struct we're doing all this for 🫶
  • buf — the buffer that's holding the data you wanna send. the goods, basically 🍓
  • count — the size of that buffer, aka how much data you're sending. she's the amount AND the size, multitasking queen 👑

🔥 DESCRIPTION 🔥

so what actually happens? the function queues data for sending — like, it puts it in the send line but doesn't personally escort it out the door. to actually send the buffered data, a work queue function gets scheduled, and it does that with QUEUE_SNDBUF_DELAY. and the function returns the number of data bytes that has been buffered. so like, "here's how much I took, bestie" 💅

now for the vibe check on the return values, because these matter 😭:

  • if the device is not connected, the data is simply ignored and the function returns count. yes, your data got ghosted, but the count still comes back 🙈
  • if the buffer is full, the function returns 0. no room, no bytes, no cap 💀
  • if an existing IUCV communicaton path has been severed, you get -EPIPE back. and ooh, that one's got a purpose — it can be passed to the HVC layer to cause a tty hangup. so it's not just an error, it's a signal 🔥
ok but fr fr, keep an eye on that severed-path case — it's the one with consequences, and it's meant to travel up to the HVC layer to trigger the hangup. not just a random sad number 🌈

🦋 SEE ALSO 🦋

the kernel file lives at ./drivers/tty/hvc/hvc_iucv.c and honestly the whole friend group is here, so let's give them all their moment 💜

and that's the whole page, bestie, no notes ✨ no skips, no summarizing, we read the WHOLE thing 📚

cute little sign-off: this one's from ./drivers/tty/hvc (that's the source, mwah 💋), dated October 2026, and it's the hvc_iucv_queue(9) page. periodt. 🎀💖🌈

📦 where this page comes from