Accessing rnglists section

Example showing access to rnglists on an Attribute.

This is accessing DWARF5 .debug_rnglists. The section first appears in DWARF5.

*/
int example_rnglist_for_attribute(Dwarf_Attribute attr,
    Dwarf_Unsigned attrvalue,Dwarf_Error *error)
{
    /*  attrvalue must be the DW_AT_ranges
        DW_FORM_rnglistx or DW_FORM_sec_offset value
        extracted from attr. */
    int                 res = 0;
    Dwarf_Half          theform = 0;
    Dwarf_Unsigned      entries_count;
    Dwarf_Unsigned      global_offset_of_rle_set;
    Dwarf_Rnglists_Head rnglhead = 0;
    Dwarf_Unsigned      i = 0;
 
    res = dwarf_rnglists_get_rle_head(attr,
        theform,
        attrvalue,
        &rnglhead,
        &entries_count,
        &global_offset_of_rle_set,
        error);
    if (res != DW_DLV_OK) {
        return res;
    }
    for (i = 0; i < entries_count; ++i) {
        unsigned entrylen     = 0;
        unsigned       code         = 0;
        Dwarf_Unsigned rawlowpc  = 0;
        Dwarf_Unsigned rawhighpc = 0;
        Dwarf_Bool     debug_addr_unavailable = FALSE;
        Dwarf_Unsigned lowpc  = 0;
        Dwarf_Unsigned highpc = 0;
 
        /*  Actual addresses are most likely what one
            wants to know, not the lengths/offsets
            recorded in .debug_rnglists. */
        res = dwarf_get_rnglists_entry_fields_a(rnglhead,
            i,&entrylen,&code,
            &rawlowpc,&rawhighpc,
            &debug_addr_unavailable,
            &lowpc,&highpc,error);
        if (res != DW_DLV_OK) {
            dwarf_dealloc_rnglists_head(rnglhead);
            return res;
        }
        if (code == DW_RLE_end_of_list) {
            /* we are done */
            break;
        }
        if (code == DW_RLE_base_addressx ||
            code == DW_RLE_base_address) {
            /*  We do not need to use these, they
                have been accounted for already. */
            continue;
        }
        if (debug_addr_unavailable) {
            /* lowpc and highpc are not real addresses */
            continue;
        }
        /*  Here do something with lowpc and highpc, these
            are real addresses */
    }
    dwarf_dealloc_rnglists_head(rnglhead);
    return DW_DLV_OK;
}