shishi_asn1_read_optional(3)

📦
version 1.0.3 · 3 versions
, in debian bookworm, debian trixie, nixos 26.05, nixpkgs unstable, ubuntu noble, ubuntu questing, ubuntu resolute

💖 shishi_asn1_read_optional 💖

okay bestie, gather round, because today we're reading a field from an ASN.1 node and being chill about it possibly not existing. this is shishi_asn1_read_optional(3), one of the shishi man pages, and honestly? she's serving convenience and I'm obsessed. 🦋

✨ SYNOPSIS ✨

#include <shishi.h>

int shishi_asn1_read_optional(Shishi * handle, Shishi_asn1 node, const
char * field, char ** data, size_t * datalen);

like look at her. five arguments. no notes. 💅

🎀 ARGUMENTS 🎀

  • Shishi * handle — your shishi handle, aka the one you got from shishi_init(). if you didn't call that first, girl what are you doing 😭
  • Shishi_asn1 node — the ASN.1 variable you wanna read a field out of.
  • const char * field — the name of the field inside node that you're trying to read.
  • char ** data — the output buffer. it's newly allocated, and it's gonna hold your ASN.1 field data. 🫶
  • size_t * datalen — the actual size of that output buffer. keep her around, she matters.

🌸 DESCRIPTION 🌸

so the whole vibe here is: you extract data stored in an ASN.1 field, and it lands in a newly allocated buffer. that's it. that's the job. ✨

but here's the part that makes her iconic: if the field doesn't exist — like, i.e. SHISHI_ASN1_NO_ELEMENT doesn't exist energy — this function just sets datalen to 0 and succeeds anyway. no drama. no tears. 💅

and that is exactly why you'd use her. she's the go-to for reading ASN.1 fields that are marked OPTIONAL in the grammar, so you don't have to write a whole special error-handling subplot in your code. she handles the "maybe it's not there" situation so you don't have to. main character energy fr fr. 👑

⭐ RETURN VALUE ⭐

  • SHISHI_OK — slayed. it worked. ✅
  • SHISHI_ASN1_NO_VALUE — the field exists but has no value. it's giving empty. 💀
  • SHISHI_ASN1_ERROR — something went wrong otherwise. 😭

🐛 REPORTING BUGS 🐛

found a bug? don't be shy, tell the shishi people at <bug-shishi@gnu.org>. 🫶

Copyright © 2002-2022 Simon Josefsson.

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

(translation: take her, share her, just keep the receipts bestie 🧾💖)

🦋 SEE ALSO 🦋

the full documentation for shishi lives in a Texinfo manual, and if the info and shishi programs are properly installed at your site, this command:

info shishi

should give you access to the complete manual. go read her, she's long but she's worth it. 📚✨

and that's a wrap, bestie!! 🌈 this was shishi_asn1_read_optional(3), from shishi version 1.0.3, and yeah she's been sitting in the manual since forever, doing her little optional-field thing. no cap. 💜🎀

mwah 💅

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