text: #ifndef __CURL_TYPECHECK_GCC_H
  #define __CURL_TYPECHECK_GCC_H
  /***************************************************************************
   *                                  _   _ ____  _
   *  Project                     ___| | | |  _ \| |
   *                             / __| | | | |_) | |
   *                            | (__| |_| |  _ <| |___
   *                             \___|\___/|_| \_\_____|
   *
   * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
   *
   * This software is licensed as described in the file COPYING, which
   * you should have received as part of this distribution. The terms
   * are also available at http://curl.haxx.se/docs/copyright.html.
   *
   * You may opt to use, copy, modify, merge, publish, distribute and/or sell
   * copies of the Software, and permit persons to whom the Software is
   * furnished to do so, under the terms of the COPYING file.
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
   * KIND, either express or implied.
   *
   ***************************************************************************/
  
  /* wraps curl_easy_setopt() with typechecking */
  
  /* To add a new kind of warning, add an
   *   if(_curl_is_sometype_option(_curl_opt))
   *     if(!_curl_is_sometype(value))
   *       _curl_easy_setopt_err_sometype();
   * block and define _curl_is_sometype_option, _curl_is_sometype and
   * _curl_easy_setopt_err_sometype below
   *
   * NOTE: We use two nested 'if' statements here instead of the && operator, in
   *       order to work around gcc bug #32061.  It affects only gcc 4.3.x/4.4.x
   *       when compiling with -Wlogical-op.
   *
   * To add an option that uses the same type as an existing option, you'll just
   * need to extend the appropriate _curl_*_option macro
   */
  #define curl_easy_setopt(handle, option, value)                               \
  __extension__ ({                                                              \
    __typeof__ (option) _curl_opt = option;                                     \
    if(__builtin_constant_p(_curl_opt)) {                                       \
      if(_curl_is_long_option(_curl_opt))                                       \
        if(!_curl_is_long(value))                                               \
          _curl_easy_setopt_err_long();                                         \
      if(_curl_is_off_t_option(_curl_opt))                                      \
        if(!_curl_is_off_t(value))                                              \
          _curl_easy_setopt_err_curl_off_t();                                   \
      if(_curl_is_string_option(_curl_opt))                                     \
        if(!_curl_is_string(value))                                             \
          _curl_easy_setopt_err_string();                                       \
      if(_curl_is_write_cb_option(_curl_opt))                                   \
        if(!_curl_is_write_cb(value))                                           \
          _curl_easy_setopt_err_write_callback();                               \
      if((_curl_opt) == CURLOPT_READFUNCTION)                                   \
        if(!_curl_is_read_cb(value))                                            \
          _curl_easy_setopt_err_read_cb();                                      \
      if((_curl_opt) == CURLOPT_IOCTLFUNCTION)                                  \
        if(!_curl_is_ioctl_cb(value))                                           \
          _curl_easy_setopt_err_ioctl_cb();                                     \
      if((_curl_opt) == CURLOPT_SOCKOPTFUNCTION)                                \
        if(!_curl_is_sockopt_cb(value))                                         \
          _curl_easy_setopt_err_sockopt_cb();                                   \
      if((_curl_opt) == CURLOPT_OPENSOCKETFUNCTION)                             \
        if(!_curl_is_opensocket_cb(value))                                      \
          _curl_easy_setopt_err_opensocket_cb();                                \
      if((_curl_opt) == CURLOPT_PROGRESSFUNCTION)                               \
        if(!_curl_is_progress_cb(value))                                        \
          _curl_easy_setopt_err_progress_cb();                                  \
      if((_curl_opt) == CURLOPT_DEBUGFUNCTION)                                  \
        if(!_curl_is_debug_cb(value))                                           \
          _curl_easy_setopt_err_debug_cb();                                     \
      if((_curl_opt) == CURLOPT_SSL_CTX_FUNCTION)                               \
        if(!_curl_is_ssl_ctx_cb(value))                                         \
          _curl_easy_setopt_err_ssl_ctx_cb();                                   \
      if(_curl_is_conv_cb_option(_curl_opt))                                    \
        if(!_curl_is_conv_cb(value))                                            \
          _curl_easy_setopt_err_conv_cb();                                      \
      if((_curl_opt) == CURLOPT_SEEKFUNCTION)                                   \
        if(!_curl_is_seek_cb(value))                                            \
          _curl_easy_setopt_err_seek_cb();                                      \
      if(_curl_is_cb_data_option(_curl_opt))                                    \
        if(!_curl_is_cb_data(value))                                            \
          _curl_easy_setopt_err_cb_data();                                      \
      if((_curl_opt) == CURLOPT_ERRORBUFFER)                                    \
        if(!_curl_is_error_buffer(value))                                       \
          _curl_easy_setopt_err_error_buffer();                                 \
      if((_curl_opt) == CURLOPT_STDERR)                                         \
        if(!_curl_is_FILE(value))                                               \
          _curl_easy_setopt_err_FILE();                                         \
      if(_curl_is_postfields_option(_curl_opt))                                 \
        if(!_curl_is_postfields(value))                                         \
          _curl_easy_setopt_err_postfields();                                   \
      if((_curl_opt) == CURLOPT_HTTPPOST)                                       \
        if(!_curl_is_arr((value), struct curl_httppost))                        \
          _curl_easy_setopt_err_curl_httpost();                                 \
      if(_curl_is_slist_option(_curl_opt))                                      \
        if(!_curl_is_arr((value), struct curl_slist))                           \
          _curl_easy_setopt_err_curl_slist();                                   \
      if((_curl_opt) == CURLOPT_SHARE)                                          \
        if(!_curl_is_ptr((value), CURLSH))                                      \
          _curl_easy_setopt_err_CURLSH();                                       \
    }                                                                           \
    curl_easy_setopt(handle, _curl_opt, value);                                 \
  })
  
  /* wraps curl_easy_getinfo() with typechecking */
  /* FIXME: don't allow const pointers */
  #define curl_easy_getinfo(handle, info, arg)                                  \
  __extension__ ({                                                              \
    __typeof__ (info) _curl_info = info;                                        \
    if(__builtin_constant_p(_curl_info)) {                                      \
      if(_curl_is_string_info(_curl_info))                                      \
        if(!_curl_is_arr((arg), char *))                                        \
          _curl_easy_getinfo_err_string();                                      \
      if(_curl_is_long_info(_curl_info))                                        \
        if(!_curl_is_arr((arg), long))                                          \
          _curl_easy_getinfo_err_long();                                        \
      if(_curl_is_double_info(_curl_info))                                      \
        if(!_curl_is_arr((arg), double))                                        \
          _curl_easy_getinfo_err_double();                                      \
      if(_curl_is_slist_info(_curl_info))                                       \
        if(!_curl_is_arr((arg), struct curl_slist *))                           \
          _curl_easy_getinfo_err_curl_slist();                                  \
    }                                                                           \
    curl_easy_getinfo(handle, _curl_info, arg);                                 \
  })
  
  /* TODO: typechecking for curl_share_setopt() and curl_multi_setopt(),
   * for now just make sure that the functions are called with three
   * arguments
   */
  #define curl_share_setopt(share,opt,param) curl_share_setopt(share,opt,param)
  #define curl_multi_setopt(handle,opt,param) curl_multi_setopt(handle,opt,param)
  
  
  /* the actual warnings, triggered by calling the _curl_easy_setopt_err*
   * functions */
  
  /* To define a new warning, use _CURL_WARNING(identifier, "message") */
  #define _CURL_WARNING(id, message)                                            \
    static void __attribute__((__warning__(message)))                           \
    __attribute__((__unused__)) __attribute__((__noinline__))                   \
    id(void) { __asm__(""); }
  
  _CURL_WARNING(_curl_easy_setopt_err_long,
    "curl_easy_setopt expects a long argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_curl_off_t,
    "curl_easy_setopt expects a curl_off_t argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_string,
                "curl_easy_setopt expects a "
                "string (char* or char[]) argument for this option"
    )
  _CURL_WARNING(_curl_easy_setopt_err_write_callback,
    "curl_easy_setopt expects a curl_write_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_read_cb,
    "curl_easy_setopt expects a curl_read_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_ioctl_cb,
    "curl_easy_setopt expects a curl_ioctl_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_sockopt_cb,
    "curl_easy_setopt expects a curl_sockopt_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_opensocket_cb,
                "curl_easy_setopt expects a "
                "curl_opensocket_callback argument for this option"
    )
  _CURL_WARNING(_curl_easy_setopt_err_progress_cb,
    "curl_easy_setopt expects a curl_progress_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_debug_cb,
    "curl_easy_setopt expects a curl_debug_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_ssl_ctx_cb,
    "curl_easy_setopt expects a curl_ssl_ctx_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_conv_cb,
    "curl_easy_setopt expects a curl_conv_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_seek_cb,
    "curl_easy_setopt expects a curl_seek_callback argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_cb_data,
                "curl_easy_setopt expects a "
                "private data pointer as argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_error_buffer,
                "curl_easy_setopt expects a "
                "char buffer of CURL_ERROR_SIZE as argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_FILE,
    "curl_easy_setopt expects a FILE* argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_postfields,
    "curl_easy_setopt expects a void* or char* argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_curl_httpost,
    "curl_easy_setopt expects a struct curl_httppost* argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_curl_slist,
    "curl_easy_setopt expects a struct curl_slist* argument for this option")
  _CURL_WARNING(_curl_easy_setopt_err_CURLSH,
    "curl_easy_setopt expects a CURLSH* argument for this option")
  
  _CURL_WARNING(_curl_easy_getinfo_err_string,
    "curl_easy_getinfo expects a pointer to char * for this info")
  _CURL_WARNING(_curl_easy_getinfo_err_long,
    "curl_easy_getinfo expects a pointer to long for this info")
  _CURL_WARNING(_curl_easy_getinfo_err_double,
    "curl_easy_getinfo expects a pointer to double for this info")
  _CURL_WARNING(_curl_easy_getinfo_err_curl_slist,
    "curl_easy_getinfo expects a pointer to struct curl_slist * for this info")
  
  /* groups of curl_easy_setops options that take the same type of argument */
  
  /* To add a new option to one of the groups, just add
   *   (option) == CURLOPT_SOMETHING
   * to the or-expression. If the option takes a long or curl_off_t, you don't
   * have to do anything
   */
  
  /* evaluates to true if option takes a long argument */
  #define _curl_is_long_option(option)                                          \
    (0 < (option) && (option) < CURLOPTTYPE_OBJECTPOINT)
  
  #define _curl_is_off_t_option(option)                                         \
    ((option) > CURLOPTTYPE_OFF_T)
  
  /* evaluates to true if option takes a char* argument */
  #define _curl_is_string_option(option)                                        \
    ((option) == CURLOPT_URL ||                                                 \
     (option) == CURLOPT_PROXY ||                                               \
     (option) == CURLOPT_INTERFACE ||                                           \
     (option) == CURLOPT_NETRC_FILE ||                                          \
     (option) == CURLOPT_USERPWD ||                                             \
     (option) == CURLOPT_USERNAME ||                                            \
     (option) == CURLOPT_PASSWORD ||                                            \
     (option) == CURLOPT_PROXYUSERPWD ||                                        \
     (option) == CURLOPT_PROXYUSERNAME ||                                       \
     (option) == CURLOPT_PROXYPASSWORD ||                                       \
     (option) == CURLOPT_NOPROXY ||                                             \
     (option) == CURLOPT_ACCEPT_ENCODING ||                                     \
     (option) == CURLOPT_REFERER ||                                             \
     (option) == CURLOPT_USERAGENT ||                                           \
     (option) == CURLOPT_COOKIE ||                                              \
     (option) == CURLOPT_COOKIEFILE ||                                          \
     (option) == CURLOPT_COOKIEJAR ||                                           \
     (option) == CURLOPT_COOKIELIST ||                                          \
     (option) == CURLOPT_FTPPORT ||                                             \
     (option) == CURLOPT_FTP_ALTERNATIVE_TO_USER ||                             \
     (option) == CURLOPT_FTP_ACCOUNT ||                                         \
     (option) == CURLOPT_RANGE ||                                               \
     (option) == CURLOPT_CUSTOMREQUEST ||                                       \
     (option) == CURLOPT_SSLCERT ||                                             \
     (option) == CURLOPT_SSLCERTTYPE ||                                         \
     (option) == CURLOPT_SSLKEY ||                                              \
     (option) == CURLOPT_SSLKEYTYPE ||                                          \
     (option) == CURLOPT_KEYPASSWD ||                                           \
     (option) == CURLOPT_SSLENGINE ||                                           \
     (option) == CURLOPT_CAINFO ||                                              \
     (option) == CURLOPT_CAPATH ||                                              \
     (option) == CURLOPT_RANDOM_FILE ||                                         \
     (option) == CURLOPT_EGDSOCKET ||                                           \
     (option) == CURLOPT_SSL_CIPHER_LIST ||                                     \
     (option) == CURLOPT_KRBLEVEL ||                                            \
     (option) == CURLOPT_SSH_HOST_PUBLIC_KEY_MD5 ||                             \
     (option) == CURLOPT_SSH_PUBLIC_KEYFILE ||                                  \
     (option) == CURLOPT_SSH_PRIVATE_KEYFILE ||                                 \
     (option) == CURLOPT_CRLFILE ||                                             \
     (option) == CURLOPT_ISSUERCERT ||                                          \
     (option) == CURLOPT_SOCKS5_GSSAPI_SERVICE ||                               \
     (option) == CURLOPT_SSH_KNOWNHOSTS ||                                      \
     (option) == CURLOPT_MAIL_FROM ||                                           \
     (option) == CURLOPT_RTSP_SESSION_ID ||                                     \
     (option) == CURLOPT_RTSP_STREAM_URI ||                                     \
     (option) == CURLOPT_RTSP_TRANSPORT ||                                      \
     (option) == CURLOPT_XOAUTH2_BEARER ||                                      \
     (option) == CURLOPT_DNS_SERVERS ||                                         \
     (option) == CURLOPT_DNS_INTERFACE ||                                       \
     (option) == CURLOPT_DNS_LOCAL_IP4 ||                                       \
     (option) == CURLOPT_DNS_LOCAL_IP6 ||                                       \
     (option) == CURLOPT_LOGIN_OPTIONS ||                                       \
     0)
  
  /* evaluates to true if option takes a curl_write_callback argument */
  #define _curl_is_write_cb_option(option)                                      \
    ((option) == CURLOPT_HEADERFUNCTION ||                                      \
     (option) == CURLOPT_WRITEFUNCTION)
  
  /* evaluates to true if option takes a curl_conv_callback argument */
  #define _curl_is_conv_cb_option(option)                                       \
    ((option) == CURLOPT_CONV_TO_NETWORK_FUNCTION ||                            \
     (option) == CURLOPT_CONV_FROM_NETWORK_FUNCTION ||                          \
     (option) == CURLOPT_CONV_FROM_UTF8_FUNCTION)
  
  /* evaluates to true if option takes a data argument to pass to a callback */
  #define _curl_is_cb_data_option(option)                                       \
    ((option) == CURLOPT_WRITEDATA ||                                           \
     (option) == CURLOPT_READDATA ||                                            \
     (option) == CURLOPT_IOCTLDATA ||                                           \
     (option) == CURLOPT_SOCKOPTDATA ||                                         \
     (option) == CURLOPT_OPENSOCKETDATA ||                                      \
     (option) == CURLOPT_PROGRESSDATA ||                                        \
     (option) == CURLOPT_HEADERDATA ||                                         \
     (option) == CURLOPT_DEBUGDATA ||                                           \
     (option) == CURLOPT_SSL_CTX_DATA ||                                        \
     (option) == CURLOPT_SEEKDATA ||                                            \
     (option) == CURLOPT_PRIVATE ||                                             \
     (option) == CURLOPT_SSH_KEYDATA ||                                         \
     (option) == CURLOPT_INTERLEAVEDATA ||                                      \
     (option) == CURLOPT_CHUNK_DATA ||                                          \
     (option) == CURLOPT_FNMATCH_DATA ||                                        \
     0)
  
  /* evaluates to true if option takes a POST data argument (void* or char*) */
  #define _curl_is_postfields_option(option)                                    \
    ((option) == CURLOPT_POSTFIELDS ||                                          \
     (option) == CURLOPT_COPYPOSTFIELDS ||                                      \
     0)
  
  /* evaluates to true if option takes a struct curl_slist * argument */
  #define _curl_is_slist_option(option)                                         \
    ((option) == CURLOPT_HTTPHEADER ||                                          \
     (option) == CURLOPT_HTTP200ALIASES ||                                      \
     (option) == CURLOPT_QUOTE ||                                               \
     (option) == CURLOPT_POSTQUOTE ||                                           \
     (option) == CURLOPT_PREQUOTE ||                                            \
     (option) == CURLOPT_TELNETOPTIONS ||                                       \
     (option) == CURLOPT_MAIL_RCPT ||                                           \
     0)
  
  /* groups of curl_easy_getinfo infos that take the same type of argument */
  
  /* evaluates to true if info expects a pointer to char * argument */
  #define _curl_is_string_info(info)                                            \
    (CURLINFO_STRING < (info) && (info) < CURLINFO_LONG)
  
  /* evaluates to true if info expects a pointer to long argument */
  #define _curl_is_long_info(info)                                              \
    (CURLINFO_LONG < (info) && (info) < CURLINFO_DOUBLE)
  
  /* evaluates to true if info expects a pointer to double argument */
  #define _curl_is_double_info(info)                                            \
    (CURLINFO_DOUBLE < (info) && (info) < CURLINFO_SLIST)
  
  /* true if info expects a pointer to struct curl_slist * argument */
  #define _curl_is_slist_info(info)                                             \
    (CURLINFO_SLIST < (info))
  
  
  /* typecheck helpers -- check whether given expression has requested type*/
  
  /* For pointers, you can use the _curl_is_ptr/_curl_is_arr macros,
   * otherwise define a new macro. Search for __builtin_types_compatible_p
   * in the GCC manual.
   * NOTE: these macros MUST NOT EVALUATE their arguments! The argument is
   * the actual expression passed to the curl_easy_setopt macro. This
   * means that you can only apply the sizeof and __typeof__ operators, no
   * == or whatsoever.
   */
  
  /* XXX: should evaluate to true iff expr is a pointer */
  #define _curl_is_any_ptr(expr)                                                \
    (sizeof(expr) == sizeof(void*))
  
  /* evaluates to true if expr is NULL */
  /* XXX: must not evaluate expr, so this check is not accurate */
  #define _curl_is_NULL(expr)                                                   \
    (__builtin_types_compatible_p(__typeof__(expr), __typeof__(NULL)))
  
  /* evaluates to true if expr is type*, const type* or NULL */
  #define _curl_is_ptr(expr, type)                                              \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), type *) ||                  \
     __builtin_types_compatible_p(__typeof__(expr), const type *))
  
  /* evaluates to true if expr is one of type[], type*, NULL or const type* */
  #define _curl_is_arr(expr, type)                                              \
    (_curl_is_ptr((expr), type) ||                                              \
     __builtin_types_compatible_p(__typeof__(expr), type []))
  
  /* evaluates to true if expr is a string */
  #define _curl_is_string(expr)                                                 \
    (_curl_is_arr((expr), char) ||                                              \
     _curl_is_arr((expr), signed char) ||                                       \
     _curl_is_arr((expr), unsigned char))
  
  /* evaluates to true if expr is a long (no matter the signedness)
   * XXX: for now, int is also accepted (and therefore short and char, which
   * are promoted to int when passed to a variadic function) */
  #define _curl_is_long(expr)                                                   \
    (__builtin_types_compatible_p(__typeof__(expr), long) ||                    \
     __builtin_types_compatible_p(__typeof__(expr), signed long) ||             \
     __builtin_types_compatible_p(__typeof__(expr), unsigned long) ||           \
     __builtin_types_compatible_p(__typeof__(expr), int) ||                     \
     __builtin_types_compatible_p(__typeof__(expr), signed int) ||              \
     __builtin_types_compatible_p(__typeof__(expr), unsigned int) ||            \
     __builtin_types_compatible_p(__typeof__(expr), short) ||                   \
     __builtin_types_compatible_p(__typeof__(expr), signed short) ||            \
     __builtin_types_compatible_p(__typeof__(expr), unsigned short) ||          \
     __builtin_types_compatible_p(__typeof__(expr), char) ||                    \
     __builtin_types_compatible_p(__typeof__(expr), signed char) ||             \
     __builtin_types_compatible_p(__typeof__(expr), unsigned char))
  
  /* evaluates to true if expr is of type curl_off_t */
  #define _curl_is_off_t(expr)                                                  \
    (__builtin_types_compatible_p(__typeof__(expr), curl_off_t))
  
  /* evaluates to true if expr is abuffer suitable for CURLOPT_ERRORBUFFER */
  /* XXX: also check size of an char[] array? */
  #define _curl_is_error_buffer(expr)                                           \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), char *) ||                  \
     __builtin_types_compatible_p(__typeof__(expr), char[]))
  
  /* evaluates to true if expr is of type (const) void* or (const) FILE* */
  #if 0
  #define _curl_is_cb_data(expr)                                                \
    (_curl_is_ptr((expr), void) ||                                              \
     _curl_is_ptr((expr), FILE))
  #else /* be less strict */
  #define _curl_is_cb_data(expr)                                                \
    _curl_is_any_ptr(expr)
  #endif
  
  /* evaluates to true if expr is of type FILE* */
  #define _curl_is_FILE(expr)                                                   \
    (__builtin_types_compatible_p(__typeof__(expr), FILE *))
  
  /* evaluates to true if expr can be passed as POST data (void* or char*) */
  #define _curl_is_postfields(expr)                                             \
    (_curl_is_ptr((expr), void) ||                                              \
     _curl_is_arr((expr), char))
  
  /* FIXME: the whole callback checking is messy...
   * The idea is to tolerate char vs. void and const vs. not const
   * pointers in arguments at least
   */
  /* helper: __builtin_types_compatible_p distinguishes between functions and
   * function pointers, hide it */
  #define _curl_callback_compatible(func, type)                                 \
    (__builtin_types_compatible_p(__typeof__(func), type) ||                    \
     __builtin_types_compatible_p(__typeof__(func), type*))
  
  /* evaluates to true if expr is of type curl_read_callback or "similar" */
  #define _curl_is_read_cb(expr)                                          \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), __typeof__(fread)) ||       \
     __builtin_types_compatible_p(__typeof__(expr), curl_read_callback) ||      \
     _curl_callback_compatible((expr), _curl_read_callback1) ||                 \
     _curl_callback_compatible((expr), _curl_read_callback2) ||                 \
     _curl_callback_compatible((expr), _curl_read_callback3) ||                 \
     _curl_callback_compatible((expr), _curl_read_callback4) ||                 \
     _curl_callback_compatible((expr), _curl_read_callback5) ||                 \
     _curl_callback_compatible((expr), _curl_read_callback6))
  typedef size_t (_curl_read_callback1)(char *, size_t, size_t, void*);
  typedef size_t (_curl_read_callback2)(char *, size_t, size_t, const void*);
  typedef size_t (_curl_read_callback3)(char *, size_t, size_t, FILE*);
  typedef size_t (_curl_read_callback4)(void *, size_t, size_t, void*);
  typedef size_t (_curl_read_callback5)(void *, size_t, size_t, const void*);
  typedef size_t (_curl_read_callback6)(void *, size_t, size_t, FILE*);
  
  /* evaluates to true if expr is of type curl_write_callback or "similar" */
  #define _curl_is_write_cb(expr)                                               \
    (_curl_is_read_cb(expr) ||                                            \
     __builtin_types_compatible_p(__typeof__(expr), __typeof__(fwrite)) ||      \
     __builtin_types_compatible_p(__typeof__(expr), curl_write_callback) ||     \
     _curl_callback_compatible((expr), _curl_write_callback1) ||                \
     _curl_callback_compatible((expr), _curl_write_callback2) ||                \
     _curl_callback_compatible((expr), _curl_write_callback3) ||                \
     _curl_callback_compatible((expr), _curl_write_callback4) ||                \
     _curl_callback_compatible((expr), _curl_write_callback5) ||                \
     _curl_callback_compatible((expr), _curl_write_callback6))
  typedef size_t (_curl_write_callback1)(const char *, size_t, size_t, void*);
  typedef size_t (_curl_write_callback2)(const char *, size_t, size_t,
                                         const void*);
  typedef size_t (_curl_write_callback3)(const char *, size_t, size_t, FILE*);
  typedef size_t (_curl_write_callback4)(const void *, size_t, size_t, void*);
  typedef size_t (_curl_write_callback5)(const void *, size_t, size_t,
                                         const void*);
  typedef size_t (_curl_write_callback6)(const void *, size_t, size_t, FILE*);
  
  /* evaluates to true if expr is of type curl_ioctl_callback or "similar" */
  #define _curl_is_ioctl_cb(expr)                                         \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_ioctl_callback) ||     \
     _curl_callback_compatible((expr), _curl_ioctl_callback1) ||                \
     _curl_callback_compatible((expr), _curl_ioctl_callback2) ||                \
     _curl_callback_compatible((expr), _curl_ioctl_callback3) ||                \
     _curl_callback_compatible((expr), _curl_ioctl_callback4))
  typedef curlioerr (_curl_ioctl_callback1)(CURL *, int, void*);
  typedef curlioerr (_curl_ioctl_callback2)(CURL *, int, const void*);
  typedef curlioerr (_curl_ioctl_callback3)(CURL *, curliocmd, void*);
  typedef curlioerr (_curl_ioctl_callback4)(CURL *, curliocmd, const void*);
  
  /* evaluates to true if expr is of type curl_sockopt_callback or "similar" */
  #define _curl_is_sockopt_cb(expr)                                       \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_sockopt_callback) ||   \
     _curl_callback_compatible((expr), _curl_sockopt_callback1) ||              \
     _curl_callback_compatible((expr), _curl_sockopt_callback2))
  typedef int (_curl_sockopt_callback1)(void *, curl_socket_t, curlsocktype);
  typedef int (_curl_sockopt_callback2)(const void *, curl_socket_t,
                                        curlsocktype);
  
  /* evaluates to true if expr is of type curl_opensocket_callback or
     "similar" */
  #define _curl_is_opensocket_cb(expr)                                    \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_opensocket_callback) ||\
     _curl_callback_compatible((expr), _curl_opensocket_callback1) ||           \
     _curl_callback_compatible((expr), _curl_opensocket_callback2) ||           \
     _curl_callback_compatible((expr), _curl_opensocket_callback3) ||           \
     _curl_callback_compatible((expr), _curl_opensocket_callback4))
  typedef curl_socket_t (_curl_opensocket_callback1)
    (void *, curlsocktype, struct curl_sockaddr *);
  typedef curl_socket_t (_curl_opensocket_callback2)
    (void *, curlsocktype, const struct curl_sockaddr *);
  typedef curl_socket_t (_curl_opensocket_callback3)
    (const void *, curlsocktype, struct curl_sockaddr *);
  typedef curl_socket_t (_curl_opensocket_callback4)
    (const void *, curlsocktype, const struct curl_sockaddr *);
  
  /* evaluates to true if expr is of type curl_progress_callback or "similar" */
  #define _curl_is_progress_cb(expr)                                      \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_progress_callback) ||  \
     _curl_callback_compatible((expr), _curl_progress_callback1) ||             \
     _curl_callback_compatible((expr), _curl_progress_callback2))
  typedef int (_curl_progress_callback1)(void *,
      double, double, double, double);
  typedef int (_curl_progress_callback2)(const void *,
      double, double, double, double);
  
  /* evaluates to true if expr is of type curl_debug_callback or "similar" */
  #define _curl_is_debug_cb(expr)                                         \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_debug_callback) ||     \
     _curl_callback_compatible((expr), _curl_debug_callback1) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback2) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback3) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback4) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback5) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback6) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback7) ||                \
     _curl_callback_compatible((expr), _curl_debug_callback8))
  typedef int (_curl_debug_callback1) (CURL *,
      curl_infotype, char *, size_t, void *);
  typedef int (_curl_debug_callback2) (CURL *,
      curl_infotype, char *, size_t, const void *);
  typedef int (_curl_debug_callback3) (CURL *,
      curl_infotype, const char *, size_t, void *);
  typedef int (_curl_debug_callback4) (CURL *,
      curl_infotype, const char *, size_t, const void *);
  typedef int (_curl_debug_callback5) (CURL *,
      curl_infotype, unsigned char *, size_t, void *);
  typedef int (_curl_debug_callback6) (CURL *,
      curl_infotype, unsigned char *, size_t, const void *);
  typedef int (_curl_debug_callback7) (CURL *,
      curl_infotype, const unsigned char *, size_t, void *);
  typedef int (_curl_debug_callback8) (CURL *,
      curl_infotype, const unsigned char *, size_t, const void *);
  
  /* evaluates to true if expr is of type curl_ssl_ctx_callback or "similar" */
  /* this is getting even messier... */
  #define _curl_is_ssl_ctx_cb(expr)                                       \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_ssl_ctx_callback) ||   \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback1) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback2) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback3) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback4) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback5) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback6) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback7) ||              \
     _curl_callback_compatible((expr), _curl_ssl_ctx_callback8))
  typedef CURLcode (_curl_ssl_ctx_callback1)(CURL *, void *, void *);
  typedef CURLcode (_curl_ssl_ctx_callback2)(CURL *, void *, const void *);
  typedef CURLcode (_curl_ssl_ctx_callback3)(CURL *, const void *, void *);
  typedef CURLcode (_curl_ssl_ctx_callback4)(CURL *, const void *, const void *);
  #ifdef HEADER_SSL_H
  /* hack: if we included OpenSSL's ssl.h, we know about SSL_CTX
   * this will of course break if we're included before OpenSSL headers...
   */
  typedef CURLcode (_curl_ssl_ctx_callback5)(CURL *, SSL_CTX, void *);
  typedef CURLcode (_curl_ssl_ctx_callback6)(CURL *, SSL_CTX, const void *);
  typedef CURLcode (_curl_ssl_ctx_callback7)(CURL *, const SSL_CTX, void *);
  typedef CURLcode (_curl_ssl_ctx_callback8)(CURL *, const SSL_CTX,
                                             const void *);
  #else
  typedef _curl_ssl_ctx_callback1 _curl_ssl_ctx_callback5;
  typedef _curl_ssl_ctx_callback1 _curl_ssl_ctx_callback6;
  typedef _curl_ssl_ctx_callback1 _curl_ssl_ctx_callback7;
  typedef _curl_ssl_ctx_callback1 _curl_ssl_ctx_callback8;
  #endif
  
  /* evaluates to true if expr is of type curl_conv_callback or "similar" */
  #define _curl_is_conv_cb(expr)                                          \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_conv_callback) ||      \
     _curl_callback_compatible((expr), _curl_conv_callback1) ||                 \
     _curl_callback_compatible((expr), _curl_conv_callback2) ||                 \
     _curl_callback_compatible((expr), _curl_conv_callback3) ||                 \
     _curl_callback_compatible((expr), _curl_conv_callback4))
  typedef CURLcode (*_curl_conv_callback1)(char *, size_t length);
  typedef CURLcode (*_curl_conv_callback2)(const char *, size_t length);
  typedef CURLcode (*_curl_conv_callback3)(void *, size_t length);
  typedef CURLcode (*_curl_conv_callback4)(const void *, size_t length);
  
  /* evaluates to true if expr is of type curl_seek_callback or "similar" */
  #define _curl_is_seek_cb(expr)                                          \
    (_curl_is_NULL(expr) ||                                                     \
     __builtin_types_compatible_p(__typeof__(expr), curl_seek_callback) ||      \
     _curl_callback_compatible((expr), _curl_seek_callback1) ||                 \
     _curl_callback_compatible((expr), _curl_seek_callback2))
  typedef CURLcode (*_curl_seek_callback1)(void *, curl_off_t, int);
  typedef CURLcode (*_curl_seek_callback2)(const void *, curl_off_t, int);
  
  
  #endif /* __CURL_TYPECHECK_GCC_H */
  