GELF_CHECKSUM(3)

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✨ GELF_CHECKSUM(3) ✨

okay so bestie, welcome to the Libelf Programmer's Manual 💖 we're doing gelf_checksum today and honestly? it's a lil cutie. let's get into it 🫶

💅 NAME 💅

gelf_checksum — compute the checksum for an ELF object file

🌸 SYNOPSIS 🌸

#include <gelf.h>

long int gelf_checksum (Elf *elf);

🦋 DESCRIPTION 🦋

So you've got this ELF object file, right, and it's referred to by elf. This function computes a checksum for it. That's the whole job. Iconic, lowkey.

It's basically a wrapper, bestie — it acts as a wrapper around elf32_checksum() and elf64_checksum(). The binary class of elf is what decides which one gets called, automatically. You don't have to pick, it just knows. main character energy tbh 👑

Now, the checksum itself is computed from permanent parts of the ELF file, and the result is repeatable. That repeatability is the whole point, so listen up: to keep it repeatable, strippable sections are NOT included when computing the checksum. SHT_NOBITS sections are also not included. Not invited to the party. 🚫

And what's it for? You can use this checksum as a value for DT_CHECKSUM. periodt.

🎀 PARAMETERS 🎀

  • elf — the ELF object file for which the checksum is to be computed. that's the one. that's the whole parameter. 💜

⭐ RETURN VALUE ⭐

  • On success → it returns the computed checksum 🎉
  • On failure → it returns -1 and sets elf_errno.
  • Special lil edge case: if elf is NULL, then -1 is returned without setting elf_errno. yeah. it just does that. 💀

Also important, no cap: the checksum is always calculated as a 4-byte value. If long int happens to be larger than 4 bytes, then the checksum gets extended by padding with zeros. So you're not getting extra checksum, you're getting extra zeros. 🫶

🌈 SEE ALSO 🌈

👑 ATTRIBUTES 👑

  • gelf_checksum() — Thread safety → MT-Safe

(yes bestie, she's thread safe. go wild. ✨)

🙈 REPORTING BUGS 🙈

Found a bug? Don't suffer in silence, tell the people:

that's the whole page, bestie — every flag, every caveat, every vibe. go forth and checksum responsibly 💖✨

— from the Libelf manual, dated 2025-12-31, page GELF_CHECKSUM(3), signing off 🎀💅

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