ELF_CNTL(3)

💖 ELF_CNTL 💖

okay bestie, so this is a page from the Libelf Programmer's Manual, section 3, and it's literally called elf_cntl. the whole vibe is "i control the ELF descriptor, you just live in it" 💅

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✨ NAME ✨

elf_cntl — perform control operations on an ELF descriptor 🎀

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🌸 SYNOPSIS 🌸

#include <libelf.h>

int elf_cntl(Elf *elf, Elf_Cmd cmd);

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🦋 DESCRIPTION 🦋

So basically you're performing control operations on the ELF descriptor elf, and what exactly you're doing is decided by the operation specified in cmd. that's it, that's the whole function. she's a dispatcher. she's a vibe curator. ✨

here are the commands she supports, and bestie, there are only two of them, so pay attention 👑

• ELF_C_FDDONE — this one tells libelf that the application is done using the file descriptor associated with the elf object. the file descriptor can then be closed immediately without affecting the in-memory ELF data. no cap, the in-memory stuff stays intact. but heads up 🚨 unless all the data has already been read from the file descriptor (that's the ELF_C_FDREAD situation below, iykyk), future operations on the Elf descriptor may fail. so like, don't be messy about it.
• ELF_C_FDREAD — this one makes libelf read the entire contents of the underlying file into memory immediately. and here's the tea: libelf generally reads and parses elements of ELF files only when they are required, she's a lazy girlie, it's a whole thing. this command instead triggers libelf to read all elements immediately. using this command ensures that ELF_C_FDDONE may be used without causing future operations on the Elf descriptor to fail. so it's giving "pre-game so the after-party goes smoothly" 🫶

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⭐ RETURN VALUE ⭐

On success, returns 0. slay, she ate 💅

On failure, it returns -1 and sets an error that can be retrieved with elf_errmsg(3). so if it flops, go ask elf_errmsg(3) what happened, she'll tell you 😭

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🌈 SEE ALSO 🌈

• libelf(3)
• elf_errmsg(3)
• elf(5)

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💜 ATTRIBUTES 💜

(the original page has this heading and then... nothing under it. iconic of her honestly. no attributes listed. we move.) 🙈

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🎀 REPORTING BUGS 🎀

found a bug? don't gatekeep, tell someone! report bugs to <elfutils-devel@sourceware.org> or hit up https://sourceware.org/bugzilla/ 🐛

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and that's the whole page, bestie!! this was ELF_CNTL(3) from the Libelf manual, dated 2025-06-17, and honestly she's short but she's powerful. go forth and control your descriptors responsibly 💖✨🌸🦋👑