Examining Section Group data

Example accessing Section Group data.

With split dwarf your libdwarf calls after than the initial open are done against the base Dwarf_Dbg and libdwarf automatically looks in the open tied dbg when and as appropriate. the tied-dbg can be detached too, see example3 link, though you must call dwarf_finish() on the detached dw_tied_dbg, the library will not do that for you..

Section groups apply to Elf COMDAT groups too.

*/
void examplesecgroup(Dwarf_Debug dbg)
{
    int res = 0;
    Dwarf_Unsigned  section_count = 0;
    Dwarf_Unsigned  group_count;
    Dwarf_Unsigned  selected_group = 0;
    Dwarf_Unsigned  group_map_entry_count = 0;
    Dwarf_Unsigned *sec_nums = 0;
    Dwarf_Unsigned *group_nums = 0;
    const char **   sec_names = 0;
    Dwarf_Error     error = 0;
    Dwarf_Unsigned  i = 0;
 
    res = dwarf_sec_group_sizes(dbg,&section_count,
        &group_count,&selected_group, &group_map_entry_count,
        &error);
    if (res != DW_DLV_OK) {
        /* Something is badly wrong*/
        return;
    }
    /*  In an object without split-dwarf sections
        or COMDAT sections we now have
        selected_group == 1. */
    sec_nums = calloc(group_map_entry_count,sizeof(Dwarf_Unsigned));
    if (!sec_nums) {
        /* FAIL. out of memory */
        return;
    }
    group_nums = calloc(group_map_entry_count,sizeof(Dwarf_Unsigned));
    if (!group_nums) {
        free(group_nums);
        /* FAIL. out of memory */
        return;
    }
    sec_names = calloc(group_map_entry_count,sizeof(char*));
    if (!sec_names) {
        free(group_nums);
        free(sec_nums);
        /* FAIL. out of memory */
        return;
    }
 
    res = dwarf_sec_group_map(dbg,group_map_entry_count,
        group_nums,sec_nums,sec_names,&error);
    if (res != DW_DLV_OK) {
        /* FAIL. Something badly wrong. */
        free(sec_names);
        free(group_nums);
        free(sec_nums);
    }
    for ( i = 0; i < group_map_entry_count; ++i) {
        /*  Now do something with
            group_nums[i],sec_nums[i],sec_names[i] */
    }
    /*  The strings are in Elf data.
        Do not free() the strings themselves.*/
    free(sec_names);
    free(group_nums);
    free(sec_nums);
}