glibc/elf/Versions

libc {
  GLIBC_2.0 {
    # functions used in other libraries
    _dl_open; _dl_close; _dl_addr;
  }
  GLIBC_2.1 {
    # functions used in other libraries
    _dl_mcount_wrapper; _dl_mcount_wrapper_check;
  }
  GLIBC_2.2 {
    # this is defined in ld.so and overridden by libc
    _dl_init_first;

    # functions used in other libraries
    _dl_sym; _dl_vsym;
  }
  GLIBC_2.2.4 {
    dl_iterate_phdr;
  }
}

ld {
  GLIBC_2.0 {
    # global variables
    _dl_debug_fd;

    # Those are in the dynamic linker, but used by libc.so.
    __libc_enable_secure; _dl_catch_error; _dl_check_all_versions;
    _dl_debug_initialize; _dl_debug_state; _dl_default_scope;
    _dl_global_scope_end; _dl_lookup_symbol;
    _dl_map_object; _dl_map_object_deps; _dl_object_relocation_scope;
    _dl_relocate_object; _dl_signal_error; _dl_starting_up;
    _dl_sysdep_start; _r_debug;
    _dl_global_scope; _dl_lookup_symbol_skip;
    _dl_lookup_versioned_symbol; _dl_lookup_versioned_symbol_skip;

    # Function from libc.so which must be shared with libc.
    calloc; free; malloc; realloc;
  }
  GLIBC_2.1 {
    # global variables
    _dl_profile; _dl_profile_map; _dl_profile_output; _dl_start_profile;
    _dl_loaded; _dl_main_searchlist; _dl_fpu_control; _dl_initial_searchlist;
    _dl_global_scope_alloc; __libc_stack_end;

    # functions used in other libraries
    _dl_mcount; _dl_unload_cache;
  }
  GLIBC_2.1.1 {
    # global variables
    _dl_lazy; _dl_origin_path; _dl_platformlen;

    # functions used in other libraries
    _dl_dst_count; _dl_dst_substitute;
  }
  GLIBC_2.2 {
    _dl_init; _dl_load_lock; _dl_argv; _dl_nloaded; _dl_check_map_versions;

    # this is defined in ld.so and overridden by libc
    _dl_init_first;

    # variables used elsewhere
    _dl_out_of_memory; _dl_all_dirs; _dl_init_all_dirs;
    _dl_clktck; _dl_pagesize;
  }
  GLIBC_2.2.3 {
    _dl_debug_mask; _dl_debug_printf;
  }
}