hvc_iucv_get_chars(9)

📦 version 7.3.1, in nixpkgs unstable

✨ hvc_iucv_get_chars(9) ✨

okay bestie so this is a page from the Kernel API Manual and it's all about hvc_iucv_get_chars, and honestly? it's giving "small function, big responsibilities" 💅 let's get into it.

🎀 NAME 🎀

hvc_iucv_get_chars — the HVC get_chars operation. that's it. that's the name. periodt.

🌸 SYNOPSIS 🌸

ssize_t hvc_iucv_get_chars (uint32_t vtermno , u8 *buf , size_t count );

look at her. three args, one ssize_t return. iconic behavior tbh 🫶

🦋 ARGUMENTS 🦋

  • vtermno — the HVC virtual terminal number. like, which terminal are we even talking about, y'know? that one. 💖
  • buf — a pointer to a buffer where the data gets stored. it's the little home the characters move into 🏠
  • count — the size of the buffer that's available for writing. basically "how much room do we have, bestie" — crucial info, no cap.

💜 DESCRIPTION 💜

so the HVC thread calls this method to read characters from the back-end. that's the whole vibe. 🌈

here's the tea though: if an IUCV communication path has been established, pending IUCV messages get received, and then data is copied into the buffer buf up to count bytes. no path, no party — but if that path is there? we're copying, we're receiving, we're slaying. ✨

Locking: okay this part is important so listen up 👑 — this routine gets called under an irqsave spinlock, and the routine itself locks struct hvc_iucv_private->lock so it can call the helper functions. like she's already holding a lock and then she grabs another one. main character energy fr fr. 🔥

🧚 SEE ALSO 🧚

the whole friend group, in the kernel file ./drivers/tty/hvc/hvc_iucv.c:

ngl that's a lot of cross-references but every single one of them is valid and you should absolutely go read them. iykyk 📚✨

and that's the page, bestie!! 🎀 this little gem lives over in ./drivers/tty/hvc, it's dated October 2026, and it's filed under hvc_iucv_get_chars(9). mwah, go read some kernel source 💖🦋💅

📦 where this page comes from