VNL-GEN-HEADER(1)

📦
version 1.42 · 5 versions
, in ubuntu resolute, ubuntu stonking

💖 VNL-GEN-HEADER 💖

okay bestie, so this is a page from the vnlog manual, section 1, and it's all about the tool vnl-gen-header 🎀

✨ NAME ✨

vnl-gen-header — create definition for vnlog output from C 🦋

🌸 SYNOPSIS 🌸

$ vnl-gen-header 'int w' 'uint8_t x' 'char* y' 'double z' > vnlog_fields_generated.h

like. that's it. that's the whole vibe. 💅

💜 DESCRIPTION 💜

so there's this lil C library that makes vnlog output for you, right? and here's the thing — the fields it outputs have to be known at compile time. no surprises, no last-minute additions, the compiler needs the receipts up front. 😤

so where do those fields come from? a header file. and who makes that header file? this tool right here. that's literally its whole job. 👑

for the actual instructions on how to use the library, go peek at the vnlog documentation, okay? not this page. this page is just about the header-generating bestie. 📖✨

🧚 ARGUMENTS 🧚

okay so you gotta feed this thing a list of field definitions. it's giving "gimme the deets". here's how it looks for them:

  1. first it checks the commandline 👀
  2. if the definitions aren't there, it goes and checks STDIN 📥

each definition is a string of the form "type name" — so like, one def per argument on the commandline, or one def per line on STDIN. simple as. 🍓

💡 if you're reading from STDIN: blank lines get ignored, and any line starting with # is treated as a comment. so go ahead and annotate, nobody's mad at you.

every single def represents one output field. and each field spec is literally a C-style variable declaration — a type, followed by a name. very demure, very C. 🫶

⚠️ heads up bestie: these field specs contain whitespace. so you must quote each one before handing it to the shell. no quote = chaos = the shell eats your type and name as separate words and you will simply perish. 😭

so what types can you use? let's break it down:

  • basic scalars, possibly with set widths — think char, double, int, uint32_t, unsigned int, ... you know the ones 🌈
  • a NULL-terminated string — that's char* 💫
  • a generic chunk of binary data — that's void* 🫧

and the names? they must consist entirely of letters, numbers or _. exactly like variables in C. that's the rule, that's the law, that's the assignment. ⭐

🔥 REPOSITORY 🔥

the source lives here, go be nosy:

https://github.com/dkogan/vnlog/

👑 AUTHOR 👑

Dima Kogan "<dima@secretsauce.net>" — the icon, the legend, the one who wrote it. 💖

Copyright 2016 California Institute of Technology. 🏛️

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. 🫶

and that's the whole page, bestie!! this one's from the vnlog manual, and the page itself is dated 2026-01-26. mwah, go generate some headers 💅✨
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