DWARF_GET_LOCLIST_ENTRY(3)

💖 DWARF_GET_LOCLIST_ENTRY(3) 💖

okay bestie, welcome to the Library Functions Manual side of the group chat 💅 this page is all about grabbing a DWARF location list entry, and yes it’s giving very niche but very iconic energy. 🦋

🌸 NAME 🌸

dwarf_get_loclist_entry — retrieve DWARF location list entry. That’s the whole assignment, no cap. 🎀

🎀 LIBRARY 🎀

DWARF Access Library (libdwarf, -ldwarf) ✨ link it, love it, keep it close.

✨ SYNOPSIS ✨

#include <libdwarf.h>

int
dwarf_get_loclist_entry(Dwarf_Debug dbg, Dwarf_Unsigned offset,
    Dwarf_Addr *hipc, Dwarf_Addr *lopc, Dwarf_Ptr *data,
    Dwarf_Unsigned *entry_len, Dwarf_Unsigned *next_entry,
    Dwarf_Error *err);

🫶 DESCRIPTION 🫶

Function dwarf_get_loclist_entry() retrieves a location list entry from the DWARF section .debug_loc. Main character behavior tbh. 💜

• dbg — should reference a DWARF debug context allocated using dwarf_init(3).
• offset — an offset, relative to the .debug_loc section, to the start of the desired location list entry.
• hipc — should point to a location which will hold the offset, relative to the base address of the location list entry, of the highest program counter value for the entry.
• lopc — heads up, the original DESCRIPTION literally says lowpc here 🙈 it should point to a location which will hold the offset, relative to the base address of the location list entry, of the lowest program counter value for the entry.
• data — should point to a location which will be set to a pointer to the location list data.
• entry_len — should point to a location which will hold the length in bytes of the location list data returned in argument data.
• next_entry — should point to a location which will hold the offset of the next location list entry.
• err — if it is not NULL, it will be used to store error information in case of an error.

🔥 RETURN VALUES 🔥

Function dwarf_get_loclist_entry() returns DW_DLV_OK when it succeeds. It returns DW_DLV_NO_ENTRY if there is no location list at the specified offset offset. In case of an error, it returns DW_DLV_ERROR and sets the argument err. slay, but also mind the error path bestie 🌈

🌈 EXAMPLES 🌈

To iterate through all the location list entries in the .debug_loc section, use:

Dwarf_Debug dbg;
Dwarf_Unsigned off, len, next;
Dwarf_Addr hipc, lopc;
Dwarf_Ptr data;
Dwarf_Error de;
int ret;

off = 0;
while ((ret = dwarf_get_loclist_entry(dbg, off, &hipc, &lopc, &data,
    &len, &next, &de)) == DW_DLV_OK) {
        /* ... use loclist entry ... */
        off = next;
}
if (ret == DW_DLV_ERROR)
        warnx("dwarf_get_loclist_entry failed: %s", dwarf_errmsg(de));

💀 ERRORS 💀

Function dwarf_get_loclist_entry() can fail with:

• [DW_DLE_ARGUMENT] — one of the arguments dbg, hipc, lopc, data, entry_len or next_entry was NULL.
• [DW_DLE_NO_ENTRY] — there is no location list at the specified offset offset.

🧚 SEE ALSO 🧚

dwarf(3), dwarf_loclist(3), dwarf_loclist_from_expr(3), dwarf_loclist_from_expr_a(3), dwarf_loclist_n(3).

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and that’s the whole DWARF_GET_LOCLIST_ENTRY(3) page, bestie — from the Debian source, dated July 6, 2011 💜🫶🍓