DWARF_ADD_FDE_INST(3)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

✨ DWARF_ADD_FDE_INST(3) ✨

okay bestie, so this one is from the DWARF Access Library — that's libdwarf if you're linking it, like -ldwarf 💅 — and it's literally a tiny little function that just adds one (1) call frame instruction to a frame descriptor. that's it. that's the whole vibe. 🎀

🌸 NAME 🌸

dwarf_add_fde_inst — add a call frame instruction to a DWARF frame descriptor 🦋

📚 LIBRARY 📚

DWARF Access Library (libdwarf, -ldwarf) — yes queen, link it properly 🫶

✨ SYNOPSIS ✨

#include <libdwarf.h>

Dwarf_P_Fde
dwarf_add_fde_inst(Dwarf_P_Fde fde, Dwarf_Small op, Dwarf_Unsigned val1,
    Dwarf_Unsigned val2, Dwarf_Error *err);

💜 DESCRIPTION 💜

so dwarf_add_fde_inst() does exactly what it says on the tin: it adds a call frame instruction to the DWARF frame descriptor that fde is pointing at. one instruction at a time, bestie. iconic behavior honestly 🧚

the fde argument should reference a frame descriptor that you made with dwarf_new_fde(3) — don't just grab some random one, i'm begging 😭

the op argument is the operator for the frame instruction. and no, i'm not gonna list the legal values for you, because the DWARF standard defines the set of legal values for this argument. read the spec, it's giving homework but it's necessary 📖

the val1 argument is the first operand of the frame instruction, and val2 is the second operand. two operands, one function, zero drama. 💅

and if err isn't NULL, it gets used to store error info in case something goes wrong — which, bestie, it might. 🙈

👑 RETURN VALUES 👑

on success, dwarf_add_fde_inst() returns the frame descriptor you passed in as fde — yes, it just hands it right back to you, main character energy ⭐

but if there's an error? it returns DW_DLV_BADADDR and sets the err argument. so like, check both. always. 🔥

💀 ERRORS 💀

dwarf_add_fde_inst() can fail with:

  • [DW_DLE_ARGUMENT] — argument fde was NULL. you gave it nothing. it cannot work with nothing. 😭
  • [DW_DLE_FRAME_INSTR_EXEC_ERROR] — the frame instruction operator in argument op was invalid. not a real op, bestie. the standard said no. 🚫
  • [DW_DLE_MEMORY] — an out of memory condition was encountered during the execution of the function. it ran out of room. tragic. 💀

🌈 SEE ALSO 🌈

also fr, go read The DWARF Debugging Information Format, Version 4 at http://www.dwarfstd.org/ — iykyk 📚✨

lowkey reminder: fde must be a real frame descriptor from dwarf_new_fde(3), and op must be a legal DWARF operator. no cap, those are the two things that'll get you. 🫶

and that's the page, bestie! 🎀 this one shipped with the Debian build of the manual, dated September 26, 2011 — yes, she's vintage, and she still slays 💅💖

📦 where this page comes from