put-u8(3scm)

📦 version 0-unstable-2024-02, in nixpkgs unstable

💖 NAME 💖

Hey bestie, meet put-u8(3scm) — this page is all about put-u8 and write-u8, the little cuties that write a byte to a binary output port. Manual name: put-u8(3scm). Periodt. 💅

🌈 LIBRARY 🌈

Grab the right import for your vibe:

(import (rnrs))                     ;R6RS
(import (rnrs io ports))            ;R6RS
(import (scheme base))              ;R7RS

✨ SYNOPSIS ✨

(put-u8 binary-output-port byte)    ;R6RS
(write-u8 byte)                     ;R7RS
(write-u8 byte binary-output-port)  ;R7RS

🦋 DESCRIPTION 🦋

It writes the byte to the given binary-output-port. That's the whole assignment, bestie — no cap. 💖

🎀 IMPLEMENTATION NOTES 🎀

Chibi Scheme

The current-output-port(3scm) at program start is both textual and binary. It should normally not be possible to use write-u8 on the current output port before rebinding it to a binary output port (which is not possible in R6RS). So yeah, lowkey a little situation there. 😭

🌸 RETURN VALUES 🌸

R6RS

Returns unspecified values. The vibe is “you get something, but it's not the main character.” ✨

R7RS

Returns a unspecified value. Yes, exactly like that. 💀

🧚 EXAMPLES 🧚

;; R7RS code to create a file with the single line "A"
(call-with-port (open-output-file "test.txt")
 (lambda (p)
   (write-u8 65 p)
   (write-u8 10 p)))

💜 APPLICATION USAGE 💜

Commonly used in applications that create binary files or other binary data. There is often a mix of single bytes intermixed with larger writes with put-bytevector(3scm). Basically, it's giving “tiny byte, big file energy.” 🫶

🔥 ERRORS 🔥

This procedure can raise exceptions with the following condition types:

  • &assertion (R6RS) — the wrong number of arguments was passed or an argument was outside its domain. In particular, byte must be an exact integer between 0 and 255. So bestie, keep it in range, fr fr. 😭
  • R7RS — the assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically. Not “fail catastrophically” 😭💀 — that's the actual warning, so don't play with it.

👑 SEE ALSO 👑

⭐ STANDARDS ⭐

R6RS, R7RS. Both flavors got a seat at the table. 💅

🌻 HISTORY 🌻

The put-u8 procedure is new to the reworked I/O system introduced with R6RS. The write-u8 procedure is new in R7RS and is similar to write-char(3scm) but works with binary output ports, which did not exist in R5RS. Iconic glow-up behavior, honestly. ✨

🍓 AUTHORS 🍓

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://github.com/schemedoc/manpages/. 🫶

mwah 💋 — this cutie comes from the Scheme Programmer's Manual, dated 2022-04-07, under put-u8(3scm). byeee bestie! 🎀✨

📦 where this page comes from