# Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Descriptions and uses for these constants are described within the curl_setopt(), curl_multi_setopt() and curl_getinfo() documentation.

`CURLOPT_AUTOREFERER` (integer)
  Available since PHP 5.1.0
`CURLOPT_COOKIESESSION` (integer)
  Available since PHP 5.1.0
`CURLOPT_DNS_USE_GLOBAL_CACHE` (integer)
`CURLOPT_DNS_CACHE_TIMEOUT` (integer)
`CURLOPT_FTP_SSL` (integer)
  Available since PHP 5.2.0
`CURLFTP_CREATE_DIR` (integer)
  Available since PHP 7.0.7 and cURL 7.19.3
`CURLFTP_CREATE_DIR_NONE` (integer)
  Available since PHP 7.0.7 and cURL 7.19.3
`CURLFTP_CREATE_DIR_RETRY` (integer)
  Available since PHP 7.0.7 and cURL 7.19.3
`CURLFTPSSL_TRY` (integer)
  Available since PHP 5.2.0
`CURLFTPSSL_ALL` (integer)
  Available since PHP 5.2.0
`CURLFTPSSL_CONTROL` (integer)
  Available since PHP 5.2.0
`CURLFTPSSL_NONE` (integer)
  Available since PHP 5.2.0
`CURLOPT_PRIVATE` (integer)
  Available since PHP 5.2.4
`CURLOPT_FTPSSLAUTH` (integer)
  Available since PHP 5.1.0
`CURLOPT_PORT` (integer)
`CURLOPT_FILE` (integer)
`CURLOPT_INFILE` (integer)
`CURLOPT_INFILESIZE` (integer)
`CURLOPT_URL` (integer)
`CURLOPT_PROXY` (integer)
`CURLOPT_VERBOSE` (integer)
`CURLOPT_HEADER` (integer)
`CURLOPT_HTTPHEADER` (integer)
`CURLOPT_NOPROGRESS` (integer)
`CURLOPT_NOBODY` (integer)
`CURLOPT_FAILONERROR` (integer)
`CURLOPT_UPLOAD` (integer)
`CURLOPT_POST` (integer)
`CURLOPT_FTPLISTONLY` (integer)
`CURLOPT_FTPAPPEND` (integer)
`CURLOPT_FTP_CREATE_MISSING_DIRS` (integer)
`CURLOPT_NETRC` (integer)
`CURLOPT_FOLLOWLOCATION` (integer)
  This constant is not available when open_basedir or safe_mode are enabled.
`CURLOPT_FTPASCII` (integer)
`CURLOPT_PUT` (integer)
`CURLOPT_MUTE` (integer)
`CURLOPT_USERPWD` (integer)
`CURLOPT_PROXYUSERPWD` (integer)
`CURLOPT_RANGE` (integer)
`CURLOPT_TIMEOUT` (integer)
`CURLOPT_TIMEOUT_MS` (integer)
`CURLOPT_TCP_NODELAY` (integer)
  Available since PHP 5.2.1
`CURLOPT_POSTFIELDS` (integer)
`CURLOPT_PROGRESSFUNCTION` (integer)
  Available since PHP 5.3.0
`CURLOPT_REFERER` (integer)
`CURLOPT_USERAGENT` (integer)
`CURLOPT_FTPPORT` (integer)
`CURLOPT_FTP_USE_EPSV` (integer)
`CURLOPT_LOW_SPEED_LIMIT` (integer)
`CURLOPT_LOW_SPEED_TIME` (integer)
`CURLOPT_RESUME_FROM` (integer)
`CURLOPT_COOKIE` (integer)
`CURLOPT_COOKIELIST` (integer)
  Available since PHP 5.5.0 and cURL 7.14.1
`CURLOPT_SSLCERT` (integer)
`CURLOPT_SSLCERTPASSWD` (integer)
`CURLOPT_WRITEHEADER` (integer)
`CURLOPT_SSL_VERIFYHOST` (integer)
`CURLOPT_COOKIEFILE` (integer)
`CURLOPT_SSLVERSION` (integer)
`CURL_SSLVERSION_DEFAULT` (integer)
`CURL_SSLVERSION_TLSv1` (integer)
`CURL_SSLVERSION_SSLv2` (integer)
`CURL_SSLVERSION_SSLv3` (integer)
`CURL_SSLVERSION_TLSv1_0` (integer)
  Available since PHP 5.5.19 and 5.6.3
`CURL_SSLVERSION_TLSv1_1` (integer)
  Available since PHP 5.5.19 and 5.6.3
`CURL_SSLVERSION_TLSv1_2` (integer)
  Available since PHP 5.5.19 and 5.6.3
`CURLOPT_TIMECONDITION` (integer)
`CURLOPT_TIMEVALUE` (integer)
`CURLOPT_CUSTOMREQUEST` (integer)
`CURLOPT_STDERR` (integer)
`CURLOPT_TRANSFERTEXT` (integer)
`CURLOPT_RETURNTRANSFER` (integer)
`CURLOPT_QUOTE` (integer)
`CURLOPT_POSTQUOTE` (integer)
`CURLOPT_INTERFACE` (integer)
`CURLOPT_KRB4LEVEL` (integer)
`CURLOPT_HTTPPROXYTUNNEL` (integer)
`CURLOPT_FILETIME` (integer)
`CURLOPT_WRITEFUNCTION` (integer)
`CURLOPT_READFUNCTION` (integer)
`CURLOPT_PASSWDFUNCTION` (integer)
`CURLOPT_HEADERFUNCTION` (integer)
`CURLOPT_MAXREDIRS` (integer)
`CURLOPT_MAXCONNECTS` (integer)
`CURLOPT_CLOSEPOLICY` (integer)
  Removed in PHP 5.6.0.
`CURLOPT_FRESH_CONNECT` (integer)
`CURLOPT_FORBID_REUSE` (integer)
`CURLOPT_RANDOM_FILE` (integer)
`CURLOPT_EGDSOCKET` (integer)
`CURLOPT_CONNECTTIMEOUT` (integer)
`CURLOPT_CONNECTTIMEOUT_MS` (integer)
`CURLOPT_SSL_VERIFYPEER` (integer)
`CURLOPT_CAINFO` (integer)
`CURLOPT_CAPATH` (integer)
`CURLOPT_COOKIEJAR` (integer)
`CURLOPT_SSL_CIPHER_LIST` (integer)
`CURLOPT_BINARYTRANSFER` (integer)
`CURLOPT_NOSIGNAL` (integer)
`CURLOPT_PROXYTYPE` (integer)
  Available as of cURL 7.10.
`CURLOPT_BUFFERSIZE` (integer)
`CURLOPT_HTTPGET` (integer)
`CURLOPT_HTTP_VERSION` (integer)
`CURLOPT_SSLKEY` (integer)
`CURLOPT_SSLKEYTYPE` (integer)
`CURLOPT_SSLKEYPASSWD` (integer)
`CURLOPT_SSLENGINE` (integer)
`CURLOPT_SSLENGINE_DEFAULT` (integer)
`CURLOPT_SSLCERTTYPE` (integer)
`CURLOPT_CRLF` (integer)
`CURLOPT_ENCODING` (integer)
`CURLOPT_PROXYPORT` (integer)
`CURLOPT_UNRESTRICTED_AUTH` (integer)
`CURLOPT_FTP_USE_EPRT` (integer)
`CURLOPT_HTTP200ALIASES` (integer)
`CURLOPT_HTTPAUTH` (integer)
`CURLAUTH_BASIC` (integer)
`CURLAUTH_DIGEST` (integer)
`CURLAUTH_GSSNEGOTIATE` (integer)
`CURLAUTH_NEGOTIATE` (integer)
  Available since PHP 7.0.7 and cURL 7.38.0.
`CURLAUTH_NTLM` (integer)
`CURLAUTH_NTLM_WB` (integer)
  Available since PHP 7.0.7 and cURL 7.22.0
`CURLAUTH_ANY` (integer)
`CURLAUTH_ANYSAFE` (integer)
`CURLOPT_PROXYAUTH` (integer)
`CURLOPT_MAX_RECV_SPEED_LARGE` (integer)
  Available since PHP 5.4.0 and cURL 7.15.5
`CURLOPT_MAX_SEND_SPEED_LARGE` (integer)
  Available since PHP 5.4.0 and cURL 7.15.5
`CURLOPT_HEADEROPT` (integer)
  Available since PHP 7.0.7 and cURL 7.37.0
`CURLOPT_PROXYHEADER` (integer)
  Available since PHP 7.0.7 and cURL 7.37.0
`CURLCLOSEPOLICY_LEAST_RECENTLY_USED` (integer)
  Removed in PHP 5.6.0.
`CURLCLOSEPOLICY_LEAST_TRAFFIC` (integer)
  Removed in PHP 5.6.0.
`CURLCLOSEPOLICY_SLOWEST` (integer)
  Removed in PHP 5.6.0.
`CURLCLOSEPOLICY_CALLBACK` (integer)
  Removed in PHP 5.6.0.
`CURLCLOSEPOLICY_OLDEST` (integer)
  Removed in PHP 5.6.0.
`CURLINFO_PRIVATE` (integer)
  Available since PHP 5.2.4
`CURLINFO_EFFECTIVE_URL` (integer)
`CURLINFO_HTTP_CODE` (integer)
  As of PHP 5.5.0 and cURL 7.10.8, this is a legacy alias of `CURLINFO_RESPONSE_CODE`
`CURLINFO_RESPONSE_CODE` (integer)
  Available since PHP 5.5.0 and cURL 7.10.8
`CURLINFO_HEADER_OUT` (integer)
  Available since PHP 5.1.3
`CURLINFO_HEADER_SIZE` (integer)
`CURLINFO_REQUEST_SIZE` (integer)
`CURLINFO_TOTAL_TIME` (integer)
`CURLINFO_NAMELOOKUP_TIME` (integer)
`CURLINFO_CONNECT_TIME` (integer)
`CURLINFO_PRETRANSFER_TIME` (integer)
`CURLINFO_SIZE_UPLOAD` (integer)
`CURLINFO_SIZE_DOWNLOAD` (integer)
`CURLINFO_SPEED_DOWNLOAD` (integer)
`CURLINFO_SPEED_UPLOAD` (integer)
`CURLINFO_FILETIME` (integer)
`CURLINFO_SSL_VERIFYRESULT` (integer)
`CURLINFO_CONTENT_LENGTH_DOWNLOAD` (integer)
`CURLINFO_CONTENT_LENGTH_UPLOAD` (integer)
`CURLINFO_STARTTRANSFER_TIME` (integer)
`CURLINFO_CONTENT_TYPE` (integer)
`CURLINFO_REDIRECT_TIME` (integer)
`CURLINFO_REDIRECT_COUNT` (integer)
`CURLINFO_REDIRECT_URL` (string)
  Available since PHP 5.3.7
`CURLINFO_PRIMARY_IP` (string)
  Available since PHP 5.4.7
`CURLINFO_PRIMARY_PORT` (integer)
  Available since PHP 5.4.7
`CURLINFO_LOCAL_IP` (string)
  Available since PHP 5.4.7
`CURLINFO_LOCAL_PORT` (integer)
  Available since PHP 5.4.7
`CURL_PUSH_OK` (integer)
  Available since PHP 7.1.0 and cURL 7.44.0
`CURL_PUSH_DENY` (integer)
  Available since PHP 7.1.0 and cURL 7.44.0
`CURL_REDIR_POST_301` (integer)
  Available since PHP 7.0.7 and cURL 7.18.2
`CURL_REDIR_POST_302` (integer)
  Available since PHP 7.0.7 and cURL 7.18.2
`CURL_REDIR_POST_303` (integer)
  Available since PHP 7.0.7 and cURL 7.25.1
`CURL_REDIR_POST_ALL` (integer)
  Available since PHP 7.0.7 and cURL 7.18.2
`CURL_TIMECOND_IFMODSINCE` (integer)
`CURL_TIMECOND_IFUNMODSINCE` (integer)
`CURL_TIMECOND_LASTMOD` (integer)
`CURL_VERSION_ALTSVC` (integer)
  Available since PHP 7.3.6 and cURL 7.64.1
`CURL_VERSION_ASYNCHDNS` (integer)
  Available since PHP 7.3.0 and cURL 7.10.7
`CURL_VERSION_BROTLI` (integer)
  Available since PHP 7.3.0 and cURL 7.57.0
`CURL_VERSION_CONV` (integer)
  Available since PHP 7.3.0 and cURL 7.15.4
`CURL_VERSION_CURLDEBUG` (integer)
  Available since PHP 7.3.6 and cURL 7.19.6
`CURL_VERSION_DEBUG` (integer)
  Available since PHP 7.3.0 and cURL 7.10.6
`CURL_VERSION_GSSAPI` (integer)
  Available since PHP 7.3.0 and cURL 7.38.0
`CURL_VERSION_GSSNEGOTIATE` (integer)
  Available since PHP 7.3.0 and cURL 7.10.6 (deprecated since 7.38.0)
`CURL_VERSION_IDN` (integer)
  Available since PHP 7.3.0 and cURL 7.12.0
`CURL_VERSION_MULTI_SSL` (integer)
  Available since PHP 7.3.0 and cURL 7.56.0
`CURL_VERSION_NTLM` (integer)
  Available since PHP 7.3.0 and cURL 7.10.6
`CURL_VERSION_NTLM_WB` (integer)
  Available since PHP 7.3.0 and cURL 7.22.0
`CURL_VERSION_IPV6` (integer)
`CURL_VERSION_KERBEROS4` (integer)
`CURL_VERSION_KERBEROS5` (integer)
  Available since PHP 7.0.7 and cURL 7.40.0
`CURL_VERSION_HTTP2` (integer)
  Available since PHP 5.5.24 and 5.6.8 and cURL 7.33.0
`CURL_VERSION_PSL` (integer)
  Available since PHP 7.3.6 and cURL 7.47.0
`CURL_VERSION_SPNEGO` (integer)
  Available since PHP 7.3.0 and cURL 7.10.8
`CURL_VERSION_SSPI` (integer)
  Available since PHP 7.3.0 and cURL 7.13.2
`CURL_VERSION_SSL` (integer)
`CURL_VERSION_TLSAUTH_SRP` (integer)
  Available since PHP 7.3.0 and cURL 7.21.4
`CURL_VERSION_UNIX_SOCKETS` (integer)
  Available since PHP 7.0.7 and cURL 7.40.0
`CURL_VERSION_LIBZ` (integer)
`CURLVERSION_NOW` (integer)
`CURLE_OK` (integer)
`CURLE_UNSUPPORTED_PROTOCOL` (integer)
`CURLE_FAILED_INIT` (integer)
`CURLE_URL_MALFORMAT` (integer)
`CURLE_URL_MALFORMAT_USER` (integer)
`CURLE_COULDNT_RESOLVE_PROXY` (integer)
`CURLE_COULDNT_RESOLVE_HOST` (integer)
`CURLE_COULDNT_CONNECT` (integer)
`CURLE_FTP_WEIRD_SERVER_REPLY` (integer)
`CURLE_FTP_ACCESS_DENIED` (integer)
`CURLE_FTP_USER_PASSWORD_INCORRECT` (integer)
`CURLE_FTP_WEIRD_PASS_REPLY` (integer)
`CURLE_FTP_WEIRD_USER_REPLY` (integer)
`CURLE_FTP_WEIRD_PASV_REPLY` (integer)
`CURLE_FTP_WEIRD_227_FORMAT` (integer)
`CURLE_FTP_CANT_GET_HOST` (integer)
`CURLE_FTP_CANT_RECONNECT` (integer)
`CURLE_FTP_COULDNT_SET_BINARY` (integer)
`CURLE_PARTIAL_FILE` (integer)
`CURLE_FTP_COULDNT_RETR_FILE` (integer)
`CURLE_FTP_WRITE_ERROR` (integer)
`CURLE_FTP_QUOTE_ERROR` (integer)
`CURLE_HTTP_NOT_FOUND` (integer)
`CURLE_WRITE_ERROR` (integer)
`CURLE_MALFORMAT_USER` (integer)
`CURLE_FTP_COULDNT_STOR_FILE` (integer)
`CURLE_READ_ERROR` (integer)
`CURLE_OUT_OF_MEMORY` (integer)
`CURLE_OPERATION_TIMEOUTED` (integer)
`CURLE_FTP_COULDNT_SET_ASCII` (integer)
`CURLE_FTP_PORT_FAILED` (integer)
`CURLE_FTP_COULDNT_USE_REST` (integer)
`CURLE_FTP_COULDNT_GET_SIZE` (integer)
`CURLE_HTTP_RANGE_ERROR` (integer)
`CURLE_HTTP_POST_ERROR` (integer)
`CURLE_SSL_CONNECT_ERROR` (integer)
`CURLE_FTP_BAD_DOWNLOAD_RESUME` (integer)
`CURLE_FILE_COULDNT_READ_FILE` (integer)
`CURLE_LDAP_CANNOT_BIND` (integer)
`CURLE_LDAP_SEARCH_FAILED` (integer)
`CURLE_LIBRARY_NOT_FOUND` (integer)
`CURLE_FUNCTION_NOT_FOUND` (integer)
`CURLE_ABORTED_BY_CALLBACK` (integer)
`CURLE_BAD_FUNCTION_ARGUMENT` (integer)
`CURLE_BAD_CALLING_ORDER` (integer)
`CURLE_HTTP_PORT_FAILED` (integer)
`CURLE_BAD_PASSWORD_ENTERED` (integer)
`CURLE_TOO_MANY_REDIRECTS` (integer)
`CURLE_UNKNOWN_TELNET_OPTION` (integer)
`CURLE_TELNET_OPTION_SYNTAX` (integer)
`CURLE_OBSOLETE` (integer)
`CURLE_SSL_PEER_CERTIFICATE` (integer)
`CURLE_GOT_NOTHING` (integer)
`CURLE_SSL_ENGINE_NOTFOUND` (integer)
`CURLE_SSL_ENGINE_SETFAILED` (integer)
`CURLE_SEND_ERROR` (integer)
`CURLE_RECV_ERROR` (integer)
`CURLE_SHARE_IN_USE` (integer)
`CURLE_SSL_CERTPROBLEM` (integer)
`CURLE_SSL_CIPHER` (integer)
`CURLE_SSL_CACERT` (integer)
`CURLE_BAD_CONTENT_ENCODING` (integer)
`CURLE_LDAP_INVALID_URL` (integer)
`CURLE_FILESIZE_EXCEEDED` (integer)
`CURLE_FTP_SSL_FAILED` (integer)
`CURLE_SSH` (integer)
  Available since PHP 5.3.0 and cURL 7.16.1.
`CURLFTPAUTH_DEFAULT` (integer)
  Available since PHP 5.1.0
`CURLFTPAUTH_SSL` (integer)
  Available since PHP 5.1.0
`CURLFTPAUTH_TLS` (integer)
  Available since PHP 5.1.0
`CURLPROXY_HTTP` (integer)
  Available since cURL 7.10.
`CURLPROXY_HTTP_1_0` (integer)
  Available since PHP 7.0.7 and cURL 7.19.3
`CURLPROXY_SOCKS4` (integer)
  Available since PHP 5.2.10 and cURL 7.10.
`CURLPROXY_SOCKS5` (integer)
  Available since cURL 7.10.
`CURL_NETRC_OPTIONAL` (integer)
`CURL_NETRC_IGNORED` (integer)
`CURL_NETRC_REQUIRED` (integer)
`CURL_HTTP_VERSION_NONE` (integer)
`CURL_HTTP_VERSION_1_0` (integer)
`CURL_HTTP_VERSION_1_1` (integer)
`CURL_HTTP_VERSION_2` (integer)
  Available since PHP 7.0.7 and cURL 7.43.0
`CURL_HTTP_VERSION_2_0` (integer)
  Available since PHP 5.5.24 and 5.6.8 and cURL 7.33.0
`CURL_HTTP_VERSION_2TLS` (integer)
  Available since PHP 7.0.7 and cURL 7.47.0
`CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE` (integer)
  Available since PHP 7.0.7 and cURL 7.49.0
`CURLM_CALL_MULTI_PERFORM` (integer)
`CURLM_OK` (integer)
`CURLM_BAD_HANDLE` (integer)
`CURLM_BAD_EASY_HANDLE` (integer)
`CURLM_OUT_OF_MEMORY` (integer)
`CURLM_INTERNAL_ERROR` (integer)
`CURLMSG_DONE` (integer)
`CURLOPT_KEYPASSWD` (integer)
`CURLOPT_SSH_AUTH_TYPES` (integer)
`CURLOPT_SSH_HOST_PUBLIC_KEY_MD5` (integer)
`CURLOPT_SSH_PRIVATE_KEYFILE` (integer)
`CURLOPT_SSH_PUBLIC_KEYFILE` (integer)
`CURLOPT_SSL_OPTIONS` (integer)
  Available since PHP 5.5.0 and cURL 7.25.0
`CURLSSLOPT_ALLOW_BEAST` (integer)
  Available since PHP 5.5.0 and cURL 7.25.0
`CURLSSLOPT_NO_REVOKE` (integer)
  Available since PHP 7.0.7 and cURL 7.44.0
`CURLOPT_USERNAME` (integer)
  Available since PHP 5.5.0 and cURL 7.19.1
`CURLOPT_SASL_IR` (integer)
  Available since PHP 7.0.7 and cURL 7.31.0
`CURLOPT_DNS_INTERFACE` (integer)
  Available since PHP 7.0.7 and cURL 7.33.0
`CURLOPT_DNS_LOCAL_IP4` (integer)
  Available since PHP 7.0.7 and cURL 7.33.0
`CURLOPT_DNS_LOCAL_IP6` (integer)
  Available since PHP 7.0.7 and cURL 7.33.0
`CURLOPT_XOAUTH2_BEARER` (integer)
  Available since PHP 7.0.7 and cURL 7.33.0
`CURLOPT_LOGIN_OPTIONS` (integer)
  Available since PHP 7.0.7 and cURL 7.34.0
`CURLOPT_EXPECT_100_TIMEOUT_MS` (integer)
  Available since PHP 7.0.7 and cURL 7.36.0
`CURLOPT_SSL_ENABLE_ALPN` (integer)
  Available since PHP 7.0.7 and cURL 7.36.0
`CURLOPT_SSL_ENABLE_NPN` (integer)
  Available since PHP 7.0.7 and cURL 7.36.0
`CURLOPT_PINNEDPUBLICKEY` (integer)
  Available since PHP 7.0.7 and cURL 7.39.0
`CURLOPT_UNIX_SOCKET_PATH` (integer)
  Available since PHP 7.0.7 and cURL 7.40.0
`CURLOPT_SSL_VERIFYSTATUS` (integer)
  Available since PHP 7.0.7 and cURL 7.41.0
`CURLOPT_PATH_AS_IS` (integer)
  Available since PHP 7.0.7 and cURL 7.42.0
`CURLOPT_SSL_FALSESTART` (integer)
  Available since PHP 7.0.7 and cURL 7.42.0
`CURLOPT_PIPEWAIT` (integer)
  Available since PHP 7.0.7 and cURL 7.43.0
`CURLOPT_PROXY_SERVICE_NAME` (integer)
  Available since PHP 7.0.7 and cURL 7.43.0
`CURLOPT_SERVICE_NAME` (integer)
  Available since PHP 7.0.7 and cURL 7.43.0
`CURLOPT_DEFAULT_PROTOCOL` (integer)
  Available since PHP 7.0.7 and cURL 7.45.0
`CURLOPT_STREAM_WEIGHT` (integer)
  Available since PHP 7.0.7 and cURL 7.46.0
`CURLOPT_TFTP_NO_OPTIONS` (integer)
  Available since PHP 7.0.7 and cURL 7.48.0
`CURLOPT_CONNECT_TO` (integer)
  Available since PHP 7.0.7 and cURL 7.49.0
`CURLOPT_TCP_FASTOPEN` (integer)
  Available since PHP 7.0.7 and cURL 7.49.0
`CURLOPT_TCP_KEEPALIVE` (integer)
  Available since PHP 5.5.0 and cURL 7.25.0
`CURLOPT_TCP_KEEPIDLE` (integer)
  Available since PHP 5.5.0 and cURL 7.25.0
`CURLOPT_TCP_KEEPINTVL` (integer)
  Available since PHP 5.5.0 and cURL 7.25.0
`CURLMOPT_PIPELINING` (integer)
  Available since PHP 5.5.0 and cURL 7.16.0.
`CURLMOPT_MAXCONNECTS` (integer)
  Available since PHP 5.5.0 and cURL 7.16.3.
`CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE` (integer)
  Available since PHP 7.0.7 and cURL 7.30.0
`CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE` (integer)
  Available since PHP 7.0.7 and cURL 7.30.0
`CURLMOPT_MAX_HOST_CONNECTIONS` (integer)
  Available since PHP 7.0.7 and cURL 7.30.0
`CURLMOPT_MAX_PIPELINE_LENGTH` (integer)
  Available since PHP 7.0.7 and cURL 7.30.0
`CURLMOPT_MAX_TOTAL_CONNECTIONS` (integer)
  Available since PHP 7.0.7 and cURL 7.30.0
`CURLMOPT_PUSHFUNCTION` (integer)
  Available since PHP 7.1.0 and cURL 7.44.0
`CURLSSH_AUTH_AGENT` (integer)
  Available since PHP 7.0.7 and cURL 7.28.0
`CURLSSH_AUTH_ANY` (integer)
`CURLSSH_AUTH_DEFAULT` (integer)
`CURLSSH_AUTH_HOST` (integer)
`CURLSSH_AUTH_KEYBOARD` (integer)
`CURLSSH_AUTH_NONE` (integer)
`CURLSSH_AUTH_PASSWORD` (integer)
`CURLSSH_AUTH_PUBLICKEY` (integer)
`CURL_WRAPPERS_ENABLED` (integer)
  Defined if PHP was configured with --with-curlwrappers . Moved to PECL in PHP 5.5.0.
`CURLPAUSE_ALL` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPAUSE_CONT` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPAUSE_RECV` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPAUSE_RECV_CONT` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPAUSE_SEND` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPAUSE_SEND_CONT` (integer)
  Available since PHP 5.5.0 and cURL 7.18.0.
`CURLPIPE_NOTHING` (integer)
  Available since PHP 7.0.0 and cURL 7.43.0.
`CURLPIPE_HTTP1` (integer)
  Available since PHP 7.0.0 and cURL 7.43.0.
`CURLPIPE_MULTIPLEX` (integer)
  Available since PHP 7.0.0 and cURL 7.43.0.
`CURLPROXY_SOCKS4A` (integer)
  Available since PHP 5.5.23 and PHP 5.6.7 and cURL 7.18.0.
`CURLPROXY_SOCKS5_HOSTNAME` (integer)
  Available since PHP 5.5.23 and PHP 5.6.7 and cURL 7.18.0.
`CURLHEADER_SEPARATE` (integer)
  Available since PHP 7.0.7 and cURL 7.37.0.
`CURLHEADER_UNIFIED` (integer)
  Available since PHP 7.0.7 and cURL 7.37.0.
`CURLPROTO_SMB` (integer)
  Available since PHP 7.0.7 and cURL 7.40.0.
`CURLPROTO_SMBS` (integer)
  Available since PHP 7.0.7 and cURL 7.40.0.
`CURLOPT_REQUEST_TARGET` (integer)
  Available since PHP 7.3.0 and cURL 7.55.0.
`CURLAUTH_GSSAPI` (integer)
  Available since PHP 7.3.0 and cURL 7.54.1
`CURLE_WEIRD_SERVER_REPLY` (integer)
  Available since PHP 7.3.0 and cURL 7.51.0
`CURLINFO_CONTENT_LENGTH_DOWNLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.55.0
`CURLINFO_CONTENT_LENGTH_UPLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.55.0
`CURLINFO_HTTP_VERSION` (integer)
  Available since PHP 7.3.0 and cURL 7.50.0
`CURLINFO_PROTOCOL` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLINFO_PROXY_SSL_VERIFYRESULT` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLINFO_SCHEME` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLINFO_SIZE_DOWNLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.50.0
`CURLINFO_SIZE_UPLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.50.0
`CURLINFO_SPEED_DOWNLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.50.0
`CURLINFO_SPEED_UPLOAD_T` (integer)
  Available since PHP 7.3.0 and cURL 7.50.0
`CURL_MAX_READ_SIZE` (integer)
  Available since PHP 7.3.0 and cURL 7.53.0
`CURLOPT_ABSTRACT_UNIX_SOCKET` (integer)
  Available since PHP 7.3.0 and cURL 7.53.0
`CURLOPT_KEEP_SENDING_ON_ERROR` (integer)
  Available since PHP 7.3.0 and cURL 7.51.0
`CURLOPT_PRE_PROXY` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_CAINFO` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_CAPATH` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_CRLFILE` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_KEYPASSWD` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_PINNEDPUBLICKEY` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSLCERT` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSLCERTTYPE` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSL_CIPHER_LIST` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSLKEY` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSLKEYTYPE` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSL_OPTIONS` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSL_VERIFYHOST` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSL_VERIFYPEER` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_SSLVERSION` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_TLSAUTH_PASSWORD` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_TLSAUTH_TYPE` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_PROXY_TLSAUTH_USERNAME` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLOPT_SOCKS5_AUTH` (integer)
  Available since PHP 7.3.0 and cURL 7.55.0
`CURLOPT_SUPPRESS_CONNECT_HEADERS` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURLPROXY_HTTPS` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURL_SSLVERSION_MAX_DEFAULT` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_MAX_NONE` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_MAX_TLSv1_0` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_MAX_TLSv1_1` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_MAX_TLSv1_2` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_MAX_TLSv1_3` (integer)
  Available since PHP 7.3.0 and cURL 7.54.0
`CURL_SSLVERSION_TLSv1_3` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURL_VERSION_HTTPS_PROXY` (integer)
  Available since PHP 7.3.0 and cURL 7.52.0
`CURLAUTH_BEARER` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0.
`CURLINFO_APPCONNECT_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_CONNECT_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_FILETIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.59.0
`CURLINFO_NAMELOOKUP_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_PRETRANSFER_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_REDIRECT_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_STARTTRANSFER_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLINFO_TOTAL_TIME_T` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURL_LOCK_DATA_CONNECT` (integer)
  Available since PHP 7.3.0 and cURL 7.10.0
`CURL_LOCK_DATA_PSL` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLOPT_DISALLOW_USERNAME_IN_URL` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLOPT_DNS_SHUFFLE_ADDRESSES` (integer)
  Available since PHP 7.3.0 and cURL 7.60.0
`CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS` (integer)
  Available since PHP 7.3.0 and cURL 7.59.0
`CURLOPT_HAPROXYPROTOCOL` (integer)
  Available since PHP 7.3.0 and cURL 7.60.0
`CURLOPT_PROXY_TLS13_CIPHERS` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLOPT_SSH_COMPRESSION` (integer)
  Available since PHP 7.3.0 and cURL 7.56.0
`CURLOPT_TIMEVALUE_LARGE` (integer)
  Available since PHP 7.3.0 and cURL 7.59.0
`CURLOPT_TLS13_CIPHERS` (integer)
  Available since PHP 7.3.0 and cURL 7.61.0
`CURLSSH_AUTH_GSSAPI` (integer)
  Available since PHP 7.3.0 and cURL 7.58.0
`CURLOPT_HTTP09_ALLOWED` (integer)
  Available since PHP 7.3.15 and 7.4.3, respectively, and cURL 7.64.0