openwrt/toolchain/eglibc/config/Config.in

config EGLIBC_OPTION_EGLIBC_ADVANCED_INET6
   bool "IPv6 Advanced Sockets API support (RFC3542)"
   default y
   depends EGLIBC_OPTION_EGLIBC_INET
   help
       This option group includes the functions specified by RFC 3542,
       "Advanced Sockets Application Program Interface (API) for
       IPv6".

       This option group includes the following functions:

         inet6_opt_append
         inet6_opt_find
         inet6_opt_finish
         inet6_opt_get_val
         inet6_opt_init
         inet6_alloc
         inet6_append
         inet6_find
         inet6_init
         inet6_next
         inet6_space
         inet6_opt_next
         inet6_opt_set_val
         inet6_rth_add
         inet6_rth_getaddr
         inet6_rth_init
         inet6_rth_reverse
         inet6_rth_segments
         inet6_rth_space

config EGLIBC_OPTION_EGLIBC_BACKTRACE
   bool "Functions for producing backtraces"
   default y
   help
       This option group includes functions for producing a list of
       the function calls that are currently active in a thread, from
       within the thread itself.  These functions are often used
       within signal handlers, to produce diagnostic output.

       This option group includes the following functions:

         backtrace
         backtrace_symbols
         backtrace_symbols_fd

config EGLIBC_OPTION_EGLIBC_BSD
   bool "BSD-specific functions, and their compatibility stubs"
   default y
   help
       This option group includes functions specific to BSD kernels.
       A number of these functions have stub versions that are also
       included in libraries built for non-BSD systems for
       compatibility.

       This option group includes the following functions:

         chflags
         fchflags
         lchmod
         revoke
         setlogin

config EGLIBC_OPTION_EGLIBC_CXX_TESTS
   bool "Tests that link against the standard C++ library."
   default y
   depends EGLIBC_OPTION_POSIX_WIDE_CHAR_DEVICE_IO
   depends EGLIBC_OPTION_EGLIBC_LIBM
   help
       This option group does not include any C library functions;
       instead, it controls which EGLIBC tests an ordinary 'make
       tests' runs.  With this group disabled, tests that would
       normally link against the standard C++ library are not
       run.

       The standard C++ library depends on the math library 'libm' and
       the wide character I/O functions included in EGLIBC.  If those
       option groups are disabled, this test must also be disabled.

config EGLIBC_OPTION_EGLIBC_CATGETS
   bool "Functions for accessing message catalogs"
   default y
   depends EGLIBC_OPTION_EGLIBC_LOCALE_CODE
   help
       This option group includes functions for accessing message
       catalogs: catopen, catclose, and catgets.

       This option group depends on the EGLIBC_LOCALE_CODE
       option group; if you disable that, you must also disable this.

config EGLIBC_OPTION_EGLIBC_CHARSETS
   bool "iconv/gconv character set conversion libraries"
   default y
   help

       This option group includes support for character sets other
       than ASCII (ANSI_X3.4-1968) and Unicode and ISO-10646 in their
       various encodings.  This affects both the character sets
       supported by the wide and multibyte character functions, and
       those supported by the 'iconv' functions.

       With this option group disabled, EGLIBC supports only the
       following character sets:

          ANSI_X3.4         - ASCII
          ANSI_X3.4-1968
          ANSI_X3.4-1986
          ASCII
          CP367
          CSASCII
          IBM367
          ISO-IR-6
          ISO646-US
          ISO_646.IRV:1991
          OSF00010020
          US
          US-ASCII

          10646-1:1993      - ISO 10646, in big-endian UCS4 form
          10646-1:1993/UCS4
          CSUCS4
          ISO-10646
          ISO-10646/UCS4
          OSF00010104
          OSF00010105
          OSF00010106
          UCS-4
          UCS-4BE
          UCS4

          UCS-4LE           - ISO 10646, in little-endian UCS4 form

          ISO-10646/UTF-8   - ISO 10646, in UTF-8 form
          ISO-10646/UTF8
          ISO-IR-193
          OSF05010001
          UTF-8
          UTF8

          ISO-10646/UCS2    - ISO 10646, in target-endian UCS2 form
          OSF00010100
          OSF00010101
          OSF00010102
          UCS-2
          UCS2

          UCS-2BE           - ISO 10646, in big-endian UCS2 form
          UNICODEBIG

          UCS-2LE           - ISO 10646, in little-endian UCS2 form
          UNICODELITTLE

          WCHAR_T           - EGLIBC's internal form (target-endian,
                              32-bit ISO 10646)

config EGLIBC_OPTION_EGLIBC_DB_ALIASES
   bool "Functions for accessing the mail aliases database"
   default y
   help
       This option group includues functions for looking up mail
       aliases in '/etc/aliases' or using nsswitch.  It includes the
       following functions:

         endaliasent
         getaliasbyname
         getaliasbyname_r
         getaliasent
         getaliasent_r
         setaliasent

       When this option group is disabled, the NSS service libraries
       also lack support for querying their mail alias tables.

config EGLIBC_OPTION_EGLIBC_ENVZ
   bool "Functions for handling envz-style environment vectors."
   default y
   help
       This option group contains functions for creating and operating
       on envz vectors.  An "envz vector" is a vector of strings in a
       contiguous block of memory, where each element is a name-value
       pair, and elements are separated from their neighbors by null
       characters.

       This option group includes the following functions:

        envz_add        envz_merge 
        envz_entry      envz_remove
        envz_get        envz_strip 

config EGLIBC_OPTION_EGLIBC_FSTAB
   bool "Access functions for 'fstab'"
   default y
   help
       This option group includes functions for reading the mount
       point specification table, '/etc/fstab'.  These functions are
       not included in the POSIX standard, which provides the
       'getmntent' family of functions instead.

       This option group includues the following functions:

         endfsent       getfsspec
         getfsent       setfsent
         getfsfile

config EGLIBC_OPTION_EGLIBC_GETLOGIN
   bool "The getlogin function"
   default y
   depends EGLIBC_OPTION_EGLIBC_UTMP
   help
       This function group includes the 'getlogin' and 'getlogin_r'
       functions, which return the user name associated by the login
       activity with the current process's controlling terminal.

       With this option group disabled, the 'glob' function will not
       fall back on 'getlogin' to find the user's login name for tilde
       expansion when the 'HOME' environment variable is not set.

config EGLIBC_OPTION_EGLIBC_INET
   bool "Networking support"
   default y
   help
       This option group includes networking-specific functions and
       data.  With EGLIBC_INET disabled, the EGLIBC
       installation and API changes as follows:

       - The following libraries are not installed:

         libanl
         libnsl
         libnss_compat
         libnss_dns
         libnss_hesiod
         libnss_nis
         libnss_nisplus
         libresolv
         
       - The following functions and variables are omitted from libc:

         authdes_create           hstrerror              svc_fdset
         authdes_getucred         htonl                  svc_getreq
         authdes_pk_create        htons                  svc_getreq_common
         authnone_create          if_freenameindex       svc_getreq_poll
         authunix_create          if_indextoname         svc_getreqset
         authunix_create_default  if_nameindex           svc_max_pollfd
         bindresvport             if_nametoindex         svc_pollfd
         callrpc                  in6addr_any            svcraw_create
         cbc_crypt                in6addr_loopback       svc_register
         clnt_broadcast           inet6_opt_append       svc_run
         clnt_create              inet6_opt_find         svc_sendreply
         clnt_pcreateerror        inet6_opt_finish       svctcp_create
         clnt_perrno              inet6_opt_get_val      svcudp_bufcreate
         clnt_perror              inet6_opt_init         svcudp_create
         clntraw_create           inet6_alloc     svcudp_enablecache
         clnt_spcreateerror       inet6_append    svcunix_create
         clnt_sperrno             inet6_find      svcunixfd_create
         clnt_sperror             inet6_init      svc_unregister
         clnttcp_create           inet6_next      user2netname
         clntudp_bufcreate        inet6_space     xdecrypt
         clntudp_create           inet6_opt_next         xdr_accepted_reply
         clntunix_create          inet6_opt_set_val      xdr_array
         des_setparity            inet6_rth_add          xdr_authdes_cred
         ecb_crypt                inet6_rth_getaddr      xdr_authdes_verf
         endaliasent              inet6_rth_init         xdr_authunix_parms
         endhostent               inet6_rth_reverse      xdr_bool
         endnetent                inet6_rth_segments     xdr_bytes
         endnetgrent              inet6_rth_space        xdr_callhdr
         endprotoent              inet_addr              xdr_callmsg
         endrpcent                inet_aton              xdr_char
         endservent               inet_lnaof             xdr_cryptkeyarg
         ether_aton               inet_makeaddr          xdr_cryptkeyarg2
         ether_aton_r             inet_netof             xdr_cryptkeyres
         ether_hostton            inet_network           xdr_des_block
         ether_line               inet_nsap_addr         xdr_double
         ether_ntoa               inet_nsap_ntoa         xdr_enum
         ether_ntoa_r             inet_ntoa              xdr_float
         ether_ntohost            inet_ntop              xdr_free
         freeaddrinfo             inet_pton              xdr_getcredres
         freeifaddrs              innetgr                xdr_hyper
         gai_strerror             iruserok               xdr_int
         getaddrinfo              iruserok_af            xdr_int16_t
         getaliasbyname           key_decryptsession     xdr_int32_t
         getaliasbyname_r         key_decryptsession_pk  xdr_int64_t
         getaliasent              key_encryptsession     xdr_int8_t
         getaliasent_r            key_encryptsession_pk  xdr_keybuf
         gethostbyaddr            key_gendes             xdr_key_netstarg
         gethostbyaddr_r          key_get_conv           xdr_key_netstres
         gethostbyname            key_secretkey_is_set   xdr_keystatus
         gethostbyname2           key_setnet             xdr_long
         gethostbyname2_r         key_setsecret          xdr_longlong_t
         gethostbyname_r          netname2host           xdrmem_create
         gethostent               netname2user           xdr_netnamestr
         gethostent_r             ntohl                  xdr_netobj
         getifaddrs               ntohs                  xdr_opaque
         getipv4sourcefilter      passwd2des             xdr_opaque_auth
         get_myaddress            pmap_getmaps           xdr_pmap
         getnameinfo              pmap_getport           xdr_pmaplist
         getnetbyaddr             pmap_rmtcall           xdr_pointer
         getnetbyaddr_r           pmap_set               xdr_quad_t
         getnetbyname             pmap_unset             xdrrec_create
         getnetbyname_r           rcmd                   xdrrec_endofrecord
         getnetent                rcmd_af                xdrrec_eof
         getnetent_r              registerrpc            xdrrec_skiprecord
         getnetgrent              res_init               xdr_reference
         getnetgrent_r            rexec                  xdr_rejected_reply
         getnetname               rexec_af               xdr_replymsg
         getprotobyname           rexecoptions           xdr_rmtcall_args
         getprotobyname_r         rpc_createerr          xdr_rmtcallres
         getprotobynumber         rresvport              xdr_short
         getprotobynumber_r       rresvport_af           xdr_sizeof
         getprotoent              rtime                  xdrstdio_create
         getprotoent_r            ruserok                xdr_string
         getpublickey             ruserok_af             xdr_u_char
         getrpcbyname             ruserpass              xdr_u_hyper
         getrpcbyname_r           setaliasent            xdr_u_int
         getrpcbynumber           sethostent             xdr_uint16_t
         getrpcbynumber_r         setipv4sourcefilter    xdr_uint32_t
         getrpcent                setnetent              xdr_uint64_t
         getrpcent_r              setnetgrent            xdr_uint8_t
         getrpcport               setprotoent            xdr_u_long
         getsecretkey             setrpcent              xdr_u_longlong_t
         getservbyname            setservent             xdr_union
         getservbyname_r          setsourcefilter        xdr_unixcred
         getservbyport            svcauthdes_stats       xdr_u_quad_t
         getservbyport_r          svcerr_auth            xdr_u_short
         getservent               svcerr_decode          xdr_vector
         getservent_r             svcerr_noproc          xdr_void
         getsourcefilter          svcerr_noprog          xdr_wrapstring
         h_errlist                svcerr_progvers        xencrypt
         h_errno                  svcerr_systemerr       xprt_register
         herror                   svcerr_weakauth        xprt_unregister
         h_nerr                   svc_exit
         host2netname             svcfd_create

       - The rpcgen, nscd, and rpcinfo commands are not installed.

       - The 'rpc' file (a text file listing RPC services) is not installed.

       Socket-related system calls do not fall in this option group,
       because many are also used for other inter-process
       communication mechanisms.  For example, the 'syslog' routines
       use Unix-domain sockets to communicate with the syslog daemon;
       syslog is valuable in non-networked contexts.

config EGLIBC_OPTION_EGLIBC_LIBM
   bool "libm (math library)"
   default y
   help
       This option group includes the 'libm' library, containing
       mathematical functions.  If this option group is omitted, then
       an EGLIBC installation does not include shared or unshared versions
       of the math library.

       Note that this does not remove all floating-point related
       functionality from EGLIBC; for example, 'printf' and 'scanf'
       can still print and read floating-point values with this option
       group disabled.

       Note that the ISO Standard C++ library 'libstdc++' depends on
       EGLIBC's math library 'libm'.  If you disable this option
       group, you will not be able to build 'libstdc++' against the
       resulting EGLIBC installation.

config EGLIBC_OPTION_EGLIBC_LOCALES
   bool "Locale definitions"
   default y
   help
       This option group includes all locale definitions other than
       that for the "C" locale.  If this option group is omitted, then
       only the "C" locale is supported.


config EGLIBC_OPTION_EGLIBC_LOCALE_CODE
   bool "Locale functions"
   default y
   depends EGLIBC_OPTION_POSIX_C_LANG_WIDE_CHAR
   help
       This option group includes locale support functions, programs,
       and libraries.  With EGLIBC_LOCALE_FUNCTIONS disabled,
       EGLIBC supports only the 'C' locale (also known as 'POSIX'),
       and ignores the settings of the 'LANG' and 'LC_*' environment
       variables.

       With EGLIBC_LOCALE_CODE disabled, the following
       functions are omitted from libc:

         duplocale   localeconv  nl_langinfo    rpmatch  strfmon_l
         freelocale  newlocale   nl_langinfo_l  strfmon  uselocale

       Furthermore, only the LC_CTYPE and LC_TIME categories of the
       standard "C" locale are available.

       The EGLIBC_CATGETS option group depends on this option
       group; if you disable EGLIBC_LOCALE_CODE, you must also
       disable EGLIBC_CATGETS.

config EGLIBC_OPTION_EGLIBC_NIS
   bool "Support for NIS, NIS+, and the special 'compat' services."
   default y
   depends EGLIBC_OPTION_EGLIBC_INET
   depends EGLIBC_OPTION_EGLIBC_SUNRPC
   help
       This option group includes the NIS, NIS+, and 'compat' Name
       Service Switch service libraries.  When it is disabled, those
       services libraries are not installed; you should remove any
       references to them from your 'nsswitch.conf' file.

       This option group depends on the EGLIBC_INET option
       group; you must enable that to enable this option group.

config EGLIBC_OPTION_EGLIBC_NSSWITCH
   bool "Name service switch (nsswitch) support"
   default y
   help

       This option group includes support for the 'nsswitch' facility.
       With this option group enabled, all EGLIBC functions for
       accessing various system databases (passwords and groups;
       networking; aliases; public keys; and so on) consult the
       '/etc/nsswitch.conf' configuration file to decide how to handle
       queries.

       With this option group disabled, EGLIBC uses a fixed list of
       services to satisfy queries on each database, as requested by
       configuration files specified when EGLIBC is built.  Your
       'option-groups.config' file must set the following two
       variables:

       EGLIBC_NSSWITCH_FIXED_CONFIG

          Set this to the name of a file whose contents observe the
          same syntax as an ordinary '/etc/nsswitch.conf' file.  The
          EGLIBC build process parses this file just as EGLIBC would
          at run time if EGLIBC_NSSWITCH were enabled, and
          produces a C library that uses the nsswitch service
          libraries to search for database entries as this file
          specifies, instead of consulting '/etc/nsswitch.conf' at run
          time.

          This should be an absolute filename.  The EGLIBC build
          process may use it from several different working
          directories.  It may include references to Makefile
          variables like 'common-objpfx' (the top of the build tree,
          with a trailing slash), or '..' (the top of the source tree,
          with a trailing slash).

          The EGLIBC source tree includes a sample configuration file
          named 'nss/fixed-nsswitch.conf'; for simple configurations,
          you will probably want to delete references to databases not
          needed on your system.

       EGLIBC_NSSWITCH_FIXED_FUNCTIONS

          The EGLIBC build process uses this file to decide which
          functions to make available from which service libraries.
          The file 'nss/fixed-nsswitch.functions' serves as a sample
          configuration file for this setting, and explains its syntax
          and meaning in more detail.

          This should be an absolute file name.  The EGLIBC build
          process may use it from several different working
          directories.  It may include references to Makefile
          variables like 'common-objpfx' (the top of the build tree,
          with a trailing slash), or '..' (the top of the source tree,
          with a trailing slash).

          Be sure to mention each function in each service you wish to
          use.  If you do not mention a service's function here, the
          EGLIBC database access functions will not find it, even if
          it is listed in the EGLIBC_NSSWITCH_FIXED_CONFIG
          file.

       In this arrangement, EGLIBC will not use the 'dlopen' and
       'dlsym' functions to find database access functions.  Instead,
       libc hard-codes references to the service libraries' database
       access functions.  You must explicitly link your program
       against the name service libraries (those whose names start
       with 'libnss_', in the sysroot's '/lib' directory) whose
       functions you intend to use.  This arrangement helps
       system-wide static analysis tools decide which functions a
       system actually uses.

       Note that some nsswitch service libraries require other option
       groups to be enabled; for example, the EGLIBC_INET
       option group must be enabled to use the 'libnss_dns.so.2'
       service library, which uses the Domain Name System network
       protocol to answer queries.

config EGLIBC_OPTION_EGLIBC_RCMD
   bool "Support for 'rcmd' and related library functions"
   default y
   depends EGLIBC_OPTION_EGLIBC_INET
   help
      This option group includes functions for running commands on
      remote machines via the 'rsh' protocol, and doing authentication
      related to those functions.  This also includes functions that
      use the 'rexec' protocol.

      This option group includes the following functions:

        rcmd            ruserok
        rcmd_af         ruserok_af
        rexec           iruserok
        rexec_af        iruserok_af
        rresvport       ruserpass
        rresvport_af
        
config EGLIBC_OPTION_EGLIBC_SPAWN
   bool "Support for POSIX posix_spawn functions"
   default y
   help
      This option group includes the POSIX functions for executing
      programs in child processes without using 'fork' or 'vfork'.

      This option group includes the following functions:

        posix_spawn
        posix_spawnattr_destroy
        posix_spawnattr_getflags
        posix_spawnattr_getpgroup
        posix_spawnattr_getschedparam
        posix_spawnattr_getschedpolicy
        posix_spawnattr_getsigdefault
        posix_spawnattr_getsigmask
        posix_spawnattr_init
        posix_spawnattr_setflags
        posix_spawnattr_setpgroup
        posix_spawnattr_setschedparam
        posix_spawnattr_setschedpolicy
        posix_spawnattr_setsigdefault
        posix_spawnattr_setsigmask
        posix_spawn_file_actions_addclose
        posix_spawn_file_actions_adddup2
        posix_spawn_file_actions_addopen
        posix_spawn_file_actions_destroy
        posix_spawn_file_actions_init
        posix_spawnp

      This option group also provides the ability for the iconv,
      localedef, and locale programs to operate transparently on
      compressed charset definitions.  When this option group is
      disabled, those programs will only operate on uncompressed
      charmap files.

config EGLIBC_OPTION_EGLIBC_STREAMS
   bool "Support for accessing STREAMS."
   default y
   help
      This option group includes functions for reading and writing
      messages to and from STREAMS.  The STREAMS interface provides a
      uniform mechanism for implementing networking services and other
      character-based I/O.  (STREAMS are not to be confused with
      <stdio.h> FILE objects, also called 'streams'.)

      This option group includes the following functions:

        getmsg          putpmsg
        getpmsg         fattach
        isastream       fdetach
        putmsg

config EGLIBC_OPTION_EGLIBC_SUNRPC
   bool "Support for the Sun 'RPC' protocol."
   default y
   depends EGLIBC_OPTION_EGLIBC_INET
   help
      This option group includes support for the Sun RPC protocols,
      including the 'rpcgen' and 'rpcinfo' programs.

config EGLIBC_OPTION_EGLIBC_UTMP
   bool "Older access functions for 'utmp' login records"
   default y
   help
       This option group includes the older 'utent' family of
       functions for accessing user login records in the 'utmp' file.
       POSIX omits these functions in favor of the 'utxent' family,
       and they are obsolete on systems other than Linux.

       This option group includes the following functions:

         endutent
         getutent
         getutent_r
         getutid
         getutid_r
         getutline
         getutline_r
         logwtmp
         pututline
         setutent
         updwtmp
         utmpname

       This option group includes the following libraries:

         libutil.so (and libutil.a)

config EGLIBC_OPTION_EGLIBC_UTMPX
   bool "POSIX access functions for 'utmp' login records"
   default y
   depends EGLIBC_OPTION_EGLIBC_UTMP    
   help
       This option group includes the POSIX functions for reading and
       writing user login records in the 'utmp' file (usually
       '/var/run/utmp').  The POSIX functions operate on 'struct
       utmpx' structures, as opposed to the family of older 'utent'
       functions, which operate on 'struct utmp' structures.

       This option group includes the following functions:

         endutxent
         getutmp
         getutmpx
         getutxent
         getutxid
         getutxline
         pututxline
         setutxent
         updwtmpx
         utmpxname

config EGLIBC_OPTION_EGLIBC_WORDEXP
   bool "Shell-style word expansion"
   default y
   help
        This option group includes the 'wordexp' function for
        performing word expansion in the manner of the shell, and the
        accompanying 'wordfree' function.

config EGLIBC_OPTION_POSIX_C_LANG_WIDE_CHAR
   bool "ISO C library wide character functions, excluding I/O"
   default y
   help
        This option group includes the functions defined by the ISO C
        standard for working with wide and multibyte characters in
        memory.  Functions for reading and writing wide and multibyte
        characters from and to files call in the
        POSIX_WIDE_CHAR_DEVICE_IO option group.

        This option group includes the following functions:

          btowc         mbsinit       wcscspn       wcstoll
          iswalnum      mbsrtowcs     wcsftime      wcstombs
          iswalpha      mbstowcs      wcslen        wcstoul
          iswblank      mbtowc        wcsncat       wcstoull
          iswcntrl      swprintf      wcsncmp       wcstoumax
          iswctype      swscanf       wcsncpy       wcsxfrm
          iswdigit      towctrans     wcspbrk       wctob
          iswgraph      towlower      wcsrchr       wctomb
          iswlower      towupper      wcsrtombs     wctrans
          iswprint      vswprintf     wcsspn        wctype
          iswpunct      vswscanf      wcsstr        wmemchr
          iswspace      wcrtomb       wcstod        wmemcmp
          iswupper      wcscat        wcstof        wmemcpy
          iswxdigit     wcschr        wcstoimax     wmemmove
          mblen         wcscmp        wcstok        wmemset
          mbrlen        wcscoll       wcstol
          mbrtowc       wcscpy        wcstold

config EGLIBC_OPTION_POSIX_REGEXP
   bool "Regular expressions"
   default y
   help
        This option group includes the POSIX regular expression
        functions, and the associated non-POSIX extensions and
        compatibility functions.

        With POSIX_REGEXP disabled, the following functions are
        omitted from libc:

          re_comp                 re_max_failures         regcomp
          re_compile_fastmap      re_search               regerror
          re_compile_pattern      re_search_2             regexec
          re_exec                 re_set_registers        regfree
          re_match                re_set_syntax           rpmatch
          re_match_2              re_syntax_options

        Furthermore, the compatibility regexp interface defined in the
        <regexp.h> header file, 'compile', 'step', and 'advance', is
        omitted.

config EGLIBC_OPTION_POSIX_WIDE_CHAR_DEVICE_IO
   bool "Input and output functions for wide characters"
   default y
   depends EGLIBC_OPTION_POSIX_C_LANG_WIDE_CHAR
   help
        This option group includes functions for reading and writing
        wide characters to and from <stdio.h> streams.

        This option group includes the following functions:

          fgetwc        fwprintf      putwchar      vwscanf
          fgetws        fwscanf       ungetwc       wprintf
          fputwc        getwc         vfwprintf     wscanf
          fputws        getwchar      vfwscanf
          fwide         putwc         vwprintf

        This option group further includes the following unlocked
        variants of the above functions:

          fgetwc_unlocked           getwc_unlocked
          fgetws_unlocked           getwchar_unlocked
          fputwc_unlocked           putwc_unlocked
          fputws_unlocked           putwchar_unlocked
                    
        Note that the GNU standard C++ library, 'libstdc++.so', uses
        some of these functions; you will not be able to link or run
        C++ programs if you disable this option group.

        This option group also affects the behavior of the following
        functions:

          fdopen
          fopen
          fopen64
          freopen
          freopen64

        These functions all take an OPENTYPE parameter which may
        contain a string of the form ",ccs=CHARSET", indicating that
        the underlying file uses the character set named CHARSET.
        This produces a wide-oriented stream, which is only useful
        when the functions included in this option group are present.
        If the user attempts to open a file specifying a character set
        in the OPENTYPE parameter, and EGLIBC was built with this
        option group disabled, the function returns NULL, and sets
        errno to EINVAL.