ELF32_FSIZE(3)

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💖 ELF32_FSIZE(3) 💖

okay bestie, welcome to the Libelf Programmer's Manual, section 3, and today's episode is elf32_fsize and elf64_fsize — aka the girlies who do the math so you don't have to. no cap.

✨ NAME ✨

elf32_fsize, elf64_fsize — calculate the file size of an ELF data structure 🦋

🌸 SYNOPSIS 🌸

#include <libelf.h>

size_t elf32_fsize(Elf_Type type, size_t count, unsigned int version);
size_t elf64_fsize(Elf_Type type, size_t count, unsigned int version);

💅 DESCRIPTION 💅

so here's the vibe: you hand her an Elf_Type that represents some core ELF structure, you tell her how many of them you've got, and she hands you back the number of bytes you'd need for the on-disk representation in a 32-bit or a 64-bit ELF file. that's it. that's the whole job. she ate and left no crumbs 💅

the on-disk and in-memory representations of Elf_Type are assumed to be the same, which is lowkey important — she's not converting anything, she's just trusting that they match.

if you wanna know more about what Elf_Type even is, go read libelf(3), she explains it way better than I could rn 🫶

🎀 PARAMETERS 🎀

  • type — the ELF data structure type you want the file size of. like, which shape are we counting here, bestie.
  • count — how many elements of that type. one? forty? the limit does not exist (well, kind of — see RETURN VALUE 👀).
  • version — the ELF version. set this to EV_CURRENT. that is the only valid value. periodt. 💀

⭐ RETURN VALUE ⭐

she returns the size in bytes of the data structure type you asked for, times however many you asked for. simple math, iconic behavior ✨

but — if version isn't set to EV_CURRENT, or if type isn't a valid Elf_Type? she returns 0 and sets a libelf error code. not her problem, she told you. 🙈

🚨 heads up bestie: integer overflow can occur if the size of type multiplied by count is greater than SIZE_MAX. so like... don't do that. this is the part where you do a vibe check on your numbers first. 😭

👑 SEE ALSO 👑

elf_errno(3), libelf(3), elf(5)

🌈 ATTRIBUTES 🌈

for an explanation of the terms used in this section, see attributes(7).

  • Interface: elf32_fsize(), elf64_fsize()
  • Attribute: Thread safety
  • Value: MT-Safe

so yeah — she's MT-Safe, meaning multiple threads can call her at once and she won't spiral. main character energy fr fr 🔥

💀 REPORTING BUGS 💀

found a bug? not me manifesting that, but okay. report it to <elfutils-devel@sourceware.org> or hit up https://sourceware.org/bugzilla/ and tell them everything 🫶

this page is from Libelf, dated 2024-08-14 — and that's the whole manual page, bestie. you're officially fluent. go forth and calculate those file sizes. slay 💖✨🎀

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