cares-functions.m4

  tst_allow_getservbyport_r="unknown"
  tst_nargs_getservbyport_r="unknown"
  #
  AC_MSG_CHECKING([if getservbyport_r can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([getservbyport_r])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_getservbyport_r="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_getservbyport_r="no"
  ])
  #
  if test "$tst_links_getservbyport_r" = "yes"; then
    AC_MSG_CHECKING([if getservbyport_r is prototyped])
    AC_EGREP_CPP([getservbyport_r],[
      $cares_includes_netdb
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_getservbyport_r="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_getservbyport_r="no"
    ])
  fi
  #
  if test "$tst_proto_getservbyport_r" = "yes"; then
    if test "$tst_nargs_getservbyport_r" = "unknown"; then
      AC_MSG_CHECKING([if getservbyport_r takes 4 args.])
      AC_COMPILE_IFELSE([
        AC_LANG_PROGRAM([[
          $cares_includes_netdb
        ]],[[
          if(0 != getservbyport_r(0, 0, 0, 0))
            return 1;
        ]])
      ],[
        AC_MSG_RESULT([yes])
        tst_compi_getservbyport_r="yes"
        tst_nargs_getservbyport_r="4"
      ],[
        AC_MSG_RESULT([no])
        tst_compi_getservbyport_r="no"
      ])
    fi
    if test "$tst_nargs_getservbyport_r" = "unknown"; then
      AC_MSG_CHECKING([if getservbyport_r takes 5 args.])
      AC_COMPILE_IFELSE([
        AC_LANG_PROGRAM([[
          $cares_includes_netdb
        ]],[[
          if(0 != getservbyport_r(0, 0, 0, 0, 0))
            return 1;
        ]])
      ],[
        AC_MSG_RESULT([yes])
        tst_compi_getservbyport_r="yes"
        tst_nargs_getservbyport_r="5"
      ],[
        AC_MSG_RESULT([no])
        tst_compi_getservbyport_r="no"
      ])
    fi
    if test "$tst_nargs_getservbyport_r" = "unknown"; then
      AC_MSG_CHECKING([if getservbyport_r takes 6 args.])
      AC_COMPILE_IFELSE([
        AC_LANG_PROGRAM([[
          $cares_includes_netdb
        ]],[[
          if(0 != getservbyport_r(0, 0, 0, 0, 0, 0))
            return 1;
        ]])
      ],[
        AC_MSG_RESULT([yes])
        tst_compi_getservbyport_r="yes"
        tst_nargs_getservbyport_r="6"
      ],[
        AC_MSG_RESULT([no])
        tst_compi_getservbyport_r="no"
      ])
    fi
    AC_MSG_CHECKING([if getservbyport_r is compilable])
    if test "$tst_compi_getservbyport_r" = "yes"; then
      AC_MSG_RESULT([yes])
    else
      AC_MSG_RESULT([no])
    fi
  fi
  #
  if test "$tst_compi_getservbyport_r" = "yes"; then
    AC_MSG_CHECKING([if getservbyport_r usage allowed])
    if test "x$cares_disallow_getservbyport_r" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_getservbyport_r="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_getservbyport_r="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if getservbyport_r might be used])
  if test "$tst_links_getservbyport_r" = "yes" &&
     test "$tst_proto_getservbyport_r" = "yes" &&
     test "$tst_compi_getservbyport_r" = "yes" &&
     test "$tst_allow_getservbyport_r" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_GETSERVBYPORT_R, 1,
      [Define to 1 if you have the getservbyport_r function.])
    AC_DEFINE_UNQUOTED(GETSERVBYPORT_R_ARGS, $tst_nargs_getservbyport_r,
      [Specifies the number of arguments to getservbyport_r])
    if test "$tst_nargs_getservbyport_r" -eq "4"; then
      AC_DEFINE(GETSERVBYPORT_R_BUFSIZE, sizeof(struct servent_data),
        [Specifies the size of the buffer to pass to getservbyport_r])
    else
      AC_DEFINE(GETSERVBYPORT_R_BUFSIZE, 4096,
        [Specifies the size of the buffer to pass to getservbyport_r])
    fi
    ac_cv_func_getservbyport_r="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_getservbyport_r="no"
  fi
])


dnl CARES_CHECK_FUNC_INET_NTOP
dnl -------------------------------------------------
dnl Verify if inet_ntop is available, prototyped, can
dnl be compiled and seems to work. If all of these are
dnl true, and usage has not been previously disallowed
dnl with shell variable cares_disallow_inet_ntop, then
dnl HAVE_INET_NTOP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_INET_NTOP], [
  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
  AC_REQUIRE([CARES_INCLUDES_ARPA_INET])dnl
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_inet_ntop="unknown"
  tst_proto_inet_ntop="unknown"
  tst_compi_inet_ntop="unknown"
  tst_works_inet_ntop="unknown"
  tst_allow_inet_ntop="unknown"
  #
  AC_MSG_CHECKING([if inet_ntop can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([inet_ntop])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_inet_ntop="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_inet_ntop="no"
  ])
  #
  if test "$tst_links_inet_ntop" = "yes"; then
    AC_MSG_CHECKING([if inet_ntop is prototyped])
    AC_EGREP_CPP([inet_ntop],[
      $cares_includes_arpa_inet
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_inet_ntop="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_inet_ntop="no"
    ])
  fi
  #
  if test "$tst_proto_inet_ntop" = "yes"; then
    AC_MSG_CHECKING([if inet_ntop is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_arpa_inet
      ]],[[
        if(0 != inet_ntop(0, 0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_inet_ntop="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_inet_ntop="no"
    ])
  fi
  #
  dnl only do runtime verification when not cross-compiling
  if test "x$cross_compiling" != "xyes" &&
    test "$tst_compi_inet_ntop" = "yes"; then
    AC_MSG_CHECKING([if inet_ntop seems to work])
    AC_RUN_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stdlib
        $cares_includes_arpa_inet
        $cares_includes_string
      ]],[[
        char ipv6res[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
        char ipv4res[sizeof "255.255.255.255"];
        unsigned char ipv6a[26];
        unsigned char ipv4a[5];
        char *ipv6ptr = 0;
        char *ipv4ptr = 0;
        /* - */
        ipv4res[0] = '\0';
        ipv4a[0] = 0xc0;
        ipv4a[1] = 0xa8;
        ipv4a[2] = 0x64;
        ipv4a[3] = 0x01;
        ipv4a[4] = 0x01;
        /* - */
        ipv4ptr = inet_ntop(AF_INET, ipv4a, ipv4res, sizeof(ipv4res));
        if(!ipv4ptr)
          exit(1); /* fail */
        if(ipv4ptr != ipv4res)
          exit(1); /* fail */
        if(!ipv4ptr[0])
          exit(1); /* fail */
        if(memcmp(ipv4res, "192.168.100.1", 13) != 0)
          exit(1); /* fail */
        /* - */
        ipv6res[0] = '\0';
        memset(ipv6a, 0, sizeof(ipv6a));
        ipv6a[0] = 0xfe;
        ipv6a[1] = 0x80;
        ipv6a[8] = 0x02;
        ipv6a[9] = 0x14;
        ipv6a[10] = 0x4f;
        ipv6a[11] = 0xff;
        ipv6a[12] = 0xfe;
        ipv6a[13] = 0x0b;
        ipv6a[14] = 0x76;
        ipv6a[15] = 0xc8;
        ipv6a[25] = 0x01;
        /* - */
        ipv6ptr = inet_ntop(AF_INET6, ipv6a, ipv6res, sizeof(ipv6res));
        if(!ipv6ptr)
          exit(1); /* fail */
        if(ipv6ptr != ipv6res)
          exit(1); /* fail */
        if(!ipv6ptr[0])
          exit(1); /* fail */
        if(memcmp(ipv6res, "fe80::214:4fff:fe0b:76c8", 24) != 0)
          exit(1); /* fail */
        /* - */
        exit(0);
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_works_inet_ntop="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_works_inet_ntop="no"
    ])
  fi
  #
  if test "$tst_compi_inet_ntop" = "yes" &&
    test "$tst_works_inet_ntop" != "no"; then
    AC_MSG_CHECKING([if inet_ntop usage allowed])
    if test "x$cares_disallow_inet_ntop" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_inet_ntop="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_inet_ntop="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if inet_ntop might be used])
  if test "$tst_links_inet_ntop" = "yes" &&
     test "$tst_proto_inet_ntop" = "yes" &&
     test "$tst_compi_inet_ntop" = "yes" &&
     test "$tst_allow_inet_ntop" = "yes" &&
     test "$tst_works_inet_ntop" != "no"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_INET_NTOP, 1,
      [Define to 1 if you have a IPv6 capable working inet_ntop function.])
    ac_cv_func_inet_ntop="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_inet_ntop="no"
  fi
])


dnl CARES_CHECK_FUNC_INET_PTON
dnl -------------------------------------------------
dnl Verify if inet_pton is available, prototyped, can
dnl be compiled and seems to work. If all of these are
dnl true, and usage has not been previously disallowed
dnl with shell variable cares_disallow_inet_pton, then
dnl HAVE_INET_PTON will be defined.

AC_DEFUN([CARES_CHECK_FUNC_INET_PTON], [
  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
  AC_REQUIRE([CARES_INCLUDES_ARPA_INET])dnl
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_inet_pton="unknown"
  tst_proto_inet_pton="unknown"
  tst_compi_inet_pton="unknown"
  tst_works_inet_pton="unknown"
  tst_allow_inet_pton="unknown"
  #
  AC_MSG_CHECKING([if inet_pton can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([inet_pton])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_inet_pton="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_inet_pton="no"
  ])
  #
  if test "$tst_links_inet_pton" = "yes"; then
    AC_MSG_CHECKING([if inet_pton is prototyped])
    AC_EGREP_CPP([inet_pton],[
      $cares_includes_arpa_inet
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_inet_pton="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_inet_pton="no"
    ])
  fi
  #
  if test "$tst_proto_inet_pton" = "yes"; then
    AC_MSG_CHECKING([if inet_pton is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_arpa_inet
      ]],[[
        if(0 != inet_pton(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_inet_pton="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_inet_pton="no"
    ])
  fi
  #
  dnl only do runtime verification when not cross-compiling
  if test "x$cross_compiling" != "xyes" &&
    test "$tst_compi_inet_pton" = "yes"; then
    AC_MSG_CHECKING([if inet_pton seems to work])
    AC_RUN_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stdlib
        $cares_includes_arpa_inet
        $cares_includes_string
      ]],[[
        unsigned char ipv6a[16+1];
        unsigned char ipv4a[4+1];
        const char *ipv6src = "fe80::214:4fff:fe0b:76c8";
        const char *ipv4src = "192.168.100.1";
        /* - */
        memset(ipv4a, 1, sizeof(ipv4a));
        if(1 != inet_pton(AF_INET, ipv4src, ipv4a))
          exit(1); /* fail */
        /* - */
        if( (ipv4a[0] != 0xc0) ||
            (ipv4a[1] != 0xa8) ||
            (ipv4a[2] != 0x64) ||
            (ipv4a[3] != 0x01) ||
            (ipv4a[4] != 0x01) )
          exit(1); /* fail */
        /* - */
        memset(ipv6a, 1, sizeof(ipv6a));
        if(1 != inet_pton(AF_INET6, ipv6src, ipv6a))
          exit(1); /* fail */
        /* - */
        if( (ipv6a[0]  != 0xfe) ||
            (ipv6a[1]  != 0x80) ||
            (ipv6a[8]  != 0x02) ||
            (ipv6a[9]  != 0x14) ||
            (ipv6a[10] != 0x4f) ||
            (ipv6a[11] != 0xff) ||
            (ipv6a[12] != 0xfe) ||
            (ipv6a[13] != 0x0b) ||
            (ipv6a[14] != 0x76) ||
            (ipv6a[15] != 0xc8) ||
            (ipv6a[16] != 0x01) )
          exit(1); /* fail */
        /* - */
        if( (ipv6a[2]  != 0x0) ||
            (ipv6a[3]  != 0x0) ||
            (ipv6a[4]  != 0x0) ||
            (ipv6a[5]  != 0x0) ||
            (ipv6a[6]  != 0x0) ||
            (ipv6a[7]  != 0x0) )
          exit(1); /* fail */
        /* - */
        exit(0);
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_works_inet_pton="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_works_inet_pton="no"
    ])
  fi
  #
  if test "$tst_compi_inet_pton" = "yes" &&
    test "$tst_works_inet_pton" != "no"; then
    AC_MSG_CHECKING([if inet_pton usage allowed])
    if test "x$cares_disallow_inet_pton" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_inet_pton="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_inet_pton="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if inet_pton might be used])
  if test "$tst_links_inet_pton" = "yes" &&
     test "$tst_proto_inet_pton" = "yes" &&
     test "$tst_compi_inet_pton" = "yes" &&
     test "$tst_allow_inet_pton" = "yes" &&
     test "$tst_works_inet_pton" != "no"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_INET_PTON, 1,
      [Define to 1 if you have a IPv6 capable working inet_pton function.])
    ac_cv_func_inet_pton="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_inet_pton="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTL
dnl -------------------------------------------------
dnl Verify if ioctl is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_ioctl, then
dnl HAVE_IOCTL will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTL], [
  AC_REQUIRE([CARES_INCLUDES_STROPTS])dnl
  #
  tst_links_ioctl="unknown"
  tst_proto_ioctl="unknown"
  tst_compi_ioctl="unknown"
  tst_allow_ioctl="unknown"
  #
  AC_MSG_CHECKING([if ioctl can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([ioctl])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_ioctl="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_ioctl="no"
  ])
  #
  if test "$tst_links_ioctl" = "yes"; then
    AC_MSG_CHECKING([if ioctl is prototyped])
    AC_EGREP_CPP([ioctl],[
      $cares_includes_stropts
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_ioctl="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_ioctl="no"
    ])
  fi
  #
  if test "$tst_proto_ioctl" = "yes"; then
    AC_MSG_CHECKING([if ioctl is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stropts
      ]],[[
        if(0 != ioctl(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctl="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctl="no"
    ])
  fi
  #
  if test "$tst_compi_ioctl" = "yes"; then
    AC_MSG_CHECKING([if ioctl usage allowed])
    if test "x$cares_disallow_ioctl" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctl="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctl="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if ioctl might be used])
  if test "$tst_links_ioctl" = "yes" &&
     test "$tst_proto_ioctl" = "yes" &&
     test "$tst_compi_ioctl" = "yes" &&
     test "$tst_allow_ioctl" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTL, 1,
      [Define to 1 if you have the ioctl function.])
    ac_cv_func_ioctl="yes"
    CARES_CHECK_FUNC_IOCTL_FIONBIO
    CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctl="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTL_FIONBIO
dnl -------------------------------------------------
dnl Verify if ioctl with the FIONBIO command is
dnl available, can be compiled, and seems to work. If
dnl all of these are true, then HAVE_IOCTL_FIONBIO
dnl will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTL_FIONBIO], [
  #
  tst_compi_ioctl_fionbio="unknown"
  tst_allow_ioctl_fionbio="unknown"
  #
  if test "$ac_cv_func_ioctl" = "yes"; then
    AC_MSG_CHECKING([if ioctl FIONBIO is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stropts
      ]],[[
        int flags = 0;
        if(0 != ioctl(0, FIONBIO, &flags))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctl_fionbio="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctl_fionbio="no"
    ])
  fi
  #
  if test "$tst_compi_ioctl_fionbio" = "yes"; then
    AC_MSG_CHECKING([if ioctl FIONBIO usage allowed])
    if test "x$cares_disallow_ioctl_fionbio" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctl_fionbio="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctl_fionbio="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if ioctl FIONBIO might be used])
  if test "$tst_compi_ioctl_fionbio" = "yes" &&
     test "$tst_allow_ioctl_fionbio" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTL_FIONBIO, 1,
      [Define to 1 if you have a working ioctl FIONBIO function.])
    ac_cv_func_ioctl_fionbio="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctl_fionbio="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR
dnl -------------------------------------------------
dnl Verify if ioctl with the SIOCGIFADDR command is available,
dnl struct ifreq is defined, they can be compiled, and seem to
dnl work. If all of these are true, then HAVE_IOCTL_SIOCGIFADDR
dnl will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR], [
  #
  tst_compi_ioctl_siocgifaddr="unknown"
  tst_allow_ioctl_siocgifaddr="unknown"
  #
  if test "$ac_cv_func_ioctl" = "yes"; then
    AC_MSG_CHECKING([if ioctl SIOCGIFADDR is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stropts
        #include <net/if.h>
      ]],[[
        struct ifreq ifr;
        if(0 != ioctl(0, SIOCGIFADDR, &ifr))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctl_siocgifaddr="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctl_siocgifaddr="no"
    ])
  fi
  #
  if test "$tst_compi_ioctl_siocgifaddr" = "yes"; then
    AC_MSG_CHECKING([if ioctl SIOCGIFADDR usage allowed])
    if test "x$cares_disallow_ioctl_siocgifaddr" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctl_siocgifaddr="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctl_siocgifaddr="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if ioctl SIOCGIFADDR might be used])
  if test "$tst_compi_ioctl_siocgifaddr" = "yes" &&
     test "$tst_allow_ioctl_siocgifaddr" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTL_SIOCGIFADDR, 1,
      [Define to 1 if you have a working ioctl SIOCGIFADDR function.])
    ac_cv_func_ioctl_siocgifaddr="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctl_siocgifaddr="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTLSOCKET
dnl -------------------------------------------------
dnl Verify if ioctlsocket is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_ioctlsocket, then
dnl HAVE_IOCTLSOCKET will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET], [
  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
  #
  tst_links_ioctlsocket="unknown"
  tst_proto_ioctlsocket="unknown"
  tst_compi_ioctlsocket="unknown"
  tst_allow_ioctlsocket="unknown"
  #
  AC_MSG_CHECKING([if ioctlsocket can be linked])
  AC_LINK_IFELSE([
    AC_LANG_PROGRAM([[
      $cares_includes_winsock2
    ]],[[
      if(0 != ioctlsocket(0, 0, 0))
        return 1;
    ]])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_ioctlsocket="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_ioctlsocket="no"
  ])
  #
  if test "$tst_links_ioctlsocket" = "yes"; then
    AC_MSG_CHECKING([if ioctlsocket is prototyped])
    AC_EGREP_CPP([ioctlsocket],[
      $cares_includes_winsock2
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_ioctlsocket="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_ioctlsocket="no"
    ])
  fi
  #
  if test "$tst_proto_ioctlsocket" = "yes"; then
    AC_MSG_CHECKING([if ioctlsocket is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_winsock2
      ]],[[
        if(0 != ioctlsocket(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctlsocket="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctlsocket="no"
    ])
  fi
  #
  if test "$tst_compi_ioctlsocket" = "yes"; then
    AC_MSG_CHECKING([if ioctlsocket usage allowed])
    if test "x$cares_disallow_ioctlsocket" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctlsocket="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctlsocket="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if ioctlsocket might be used])
  if test "$tst_links_ioctlsocket" = "yes" &&
     test "$tst_proto_ioctlsocket" = "yes" &&
     test "$tst_compi_ioctlsocket" = "yes" &&
     test "$tst_allow_ioctlsocket" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET, 1,
      [Define to 1 if you have the ioctlsocket function.])
    ac_cv_func_ioctlsocket="yes"
    CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctlsocket="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO
dnl -------------------------------------------------
dnl Verify if ioctlsocket with the FIONBIO command is
dnl available, can be compiled, and seems to work. If
dnl all of these are true, then HAVE_IOCTLSOCKET_FIONBIO
dnl will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO], [
  #
  tst_compi_ioctlsocket_fionbio="unknown"
  tst_allow_ioctlsocket_fionbio="unknown"
  #
  if test "$ac_cv_func_ioctlsocket" = "yes"; then
    AC_MSG_CHECKING([if ioctlsocket FIONBIO is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_winsock2
      ]],[[
        int flags = 0;
        if(0 != ioctlsocket(0, FIONBIO, &flags))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctlsocket_fionbio="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctlsocket_fionbio="no"
    ])
  fi
  #
  if test "$tst_compi_ioctlsocket_fionbio" = "yes"; then
    AC_MSG_CHECKING([if ioctlsocket FIONBIO usage allowed])
    if test "x$cares_disallow_ioctlsocket_fionbio" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctlsocket_fionbio="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctlsocket_fionbio="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if ioctlsocket FIONBIO might be used])
  if test "$tst_compi_ioctlsocket_fionbio" = "yes" &&
     test "$tst_allow_ioctlsocket_fionbio" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_FIONBIO, 1,
      [Define to 1 if you have a working ioctlsocket FIONBIO function.])
    ac_cv_func_ioctlsocket_fionbio="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctlsocket_fionbio="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL
dnl -------------------------------------------------
dnl Verify if IoctlSocket is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_ioctlsocket_camel,
dnl then HAVE_IOCTLSOCKET_CAMEL will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL], [
  AC_REQUIRE([CARES_INCLUDES_STROPTS])dnl
  #
  tst_links_ioctlsocket_camel="unknown"
  tst_proto_ioctlsocket_camel="unknown"
  tst_compi_ioctlsocket_camel="unknown"
  tst_allow_ioctlsocket_camel="unknown"
  #
  AC_MSG_CHECKING([if IoctlSocket can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([IoctlSocket])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_ioctlsocket_camel="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_ioctlsocket_camel="no"
  ])
  #
  if test "$tst_links_ioctlsocket_camel" = "yes"; then
    AC_MSG_CHECKING([if IoctlSocket is prototyped])
    AC_EGREP_CPP([IoctlSocket],[
      $cares_includes_stropts
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_ioctlsocket_camel="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_ioctlsocket_camel="no"
    ])
  fi
  #
  if test "$tst_proto_ioctlsocket_camel" = "yes"; then
    AC_MSG_CHECKING([if IoctlSocket is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stropts
      ]],[[
        if(0 != IoctlSocket(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctlsocket_camel="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctlsocket_camel="no"
    ])
  fi
  #
  if test "$tst_compi_ioctlsocket_camel" = "yes"; then
    AC_MSG_CHECKING([if IoctlSocket usage allowed])
    if test "x$cares_disallow_ioctlsocket_camel" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctlsocket_camel="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctlsocket_camel="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if IoctlSocket might be used])
  if test "$tst_links_ioctlsocket_camel" = "yes" &&
     test "$tst_proto_ioctlsocket_camel" = "yes" &&
     test "$tst_compi_ioctlsocket_camel" = "yes" &&
     test "$tst_allow_ioctlsocket_camel" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_CAMEL, 1,
      [Define to 1 if you have the IoctlSocket camel case function.])
    ac_cv_func_ioctlsocket_camel="yes"
    CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctlsocket_camel="no"
  fi
])


dnl CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO
dnl -------------------------------------------------
dnl Verify if IoctlSocket with FIONBIO command is available,
dnl can be compiled, and seems to work. If all of these are
dnl true, then HAVE_IOCTLSOCKET_CAMEL_FIONBIO will be defined.

AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO], [
  #
  tst_compi_ioctlsocket_camel_fionbio="unknown"
  tst_allow_ioctlsocket_camel_fionbio="unknown"
  #
  if test "$ac_cv_func_ioctlsocket_camel" = "yes"; then
    AC_MSG_CHECKING([if IoctlSocket FIONBIO is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_stropts
      ]],[[
        long flags = 0;
        if(0 != ioctlsocket(0, FIONBIO, &flags))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_ioctlsocket_camel_fionbio="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_ioctlsocket_camel_fionbio="no"
    ])
  fi
  #
  if test "$tst_compi_ioctlsocket_camel_fionbio" = "yes"; then
    AC_MSG_CHECKING([if IoctlSocket FIONBIO usage allowed])
    if test "x$cares_disallow_ioctlsocket_camel_fionbio" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_ioctlsocket_camel_fionbio="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_ioctlsocket_camel_fionbio="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if IoctlSocket FIONBIO might be used])
  if test "$tst_compi_ioctlsocket_camel_fionbio" = "yes" &&
     test "$tst_allow_ioctlsocket_camel_fionbio" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_CAMEL_FIONBIO, 1,
      [Define to 1 if you have a working IoctlSocket camel case FIONBIO function.])
    ac_cv_func_ioctlsocket_camel_fionbio="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_ioctlsocket_camel_fionbio="no"
  fi
])


dnl CARES_CHECK_FUNC_SETSOCKOPT
dnl -------------------------------------------------
dnl Verify if setsockopt is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_setsockopt, then
dnl HAVE_SETSOCKOPT will be defined.

AC_DEFUN([CARES_CHECK_FUNC_SETSOCKOPT], [
  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
  #
  tst_links_setsockopt="unknown"
  tst_proto_setsockopt="unknown"
  tst_compi_setsockopt="unknown"
  tst_allow_setsockopt="unknown"
  #
  AC_MSG_CHECKING([if setsockopt can be linked])
  AC_LINK_IFELSE([
    AC_LANG_PROGRAM([[
      $cares_includes_winsock2
      $cares_includes_sys_socket
    ]],[[
      if(0 != setsockopt(0, 0, 0, 0, 0))
        return 1;
    ]])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_setsockopt="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_setsockopt="no"
  ])
  #
  if test "$tst_links_setsockopt" = "yes"; then
    AC_MSG_CHECKING([if setsockopt is prototyped])
    AC_EGREP_CPP([setsockopt],[
      $cares_includes_winsock2
      $cares_includes_sys_socket
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_setsockopt="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_setsockopt="no"
    ])
  fi
  #
  if test "$tst_proto_setsockopt" = "yes"; then
    AC_MSG_CHECKING([if setsockopt is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_winsock2
        $cares_includes_sys_socket
      ]],[[
        if(0 != setsockopt(0, 0, 0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_setsockopt="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_setsockopt="no"
    ])
  fi
  #
  if test "$tst_compi_setsockopt" = "yes"; then
    AC_MSG_CHECKING([if setsockopt usage allowed])
    if test "x$cares_disallow_setsockopt" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_setsockopt="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_setsockopt="no"