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Enum etc.c.curl.CurlOption

enum CurlOption : int { ... }

Enum members

NameDescription
address_scope (IPv6) Address scope
append Append instead of overwrite on upload!
autoreferer We want the referrer field set automatically when following locations
buffersize Instruct libcurl to use a smaller receive buffer
cainfo The CApath or CAfile used to validate the peer certificate this option is used only if SSL_VERIFYPEER is true
capath The CApath directory used to validate the peer certificate this option is used only if SSL_VERIFYPEER is true
certinfo Collect certificate chain info and allow it to get retrievable with CURLINFO_CERTINFO after the transfer is complete. (Unfortunately) only working with OpenSSL-powered builds.
chunk_bgn_function Directory matching callback called before downloading of an individual file (chunk) started
chunk_data Let the application define custom chunk data pointer
chunk_end_function Directory matching callback called after the file (chunk) was downloaded, or skipped
closepolicy What policy to use when closing connections when the cache is filled up
connecttimeout Time-out connect operations after this amount of seconds, if connects are OK within this time, then fine... This only aborts the connect phase. [Only works on unix-style/SIGALRM operating systems]
connecttimeout_ms Same as TIMEOUT and CONNECTTIMEOUT, but with ms resolution
connect_only no transfer, set up connection and let application use the socket by extracting it with CURLINFO_LASTSOCKET
conv_from_network_function Function that will be called to convert from the network encoding (instead of using the iconv calls in libcurl)
conv_from_utf8_function Function that will be called to convert from UTF8 (instead of using the iconv calls in libcurl) Note that this is used only for SSL certificate processing
conv_to_network_function Function that will be called to convert to the network encoding (instead of using the iconv calls in libcurl)
Set cookie in request:
cookiefile point to a file to read the initial cookies from, also enables "cookie awareness"
cookiejar Specify which file name to write all known cookies in after completed operation. Set file name to "-" (dash) to make it go to stdout.
cookielist feed cookies into cookie engine
cookiesession mark this as start of a cookie session
copypostfields POST volatile input fields.
crlf send TYPE parameter?
crlfile CRL file
customrequest Custom request, for customizing the get command like

HTTP

DELETE, TRACE and others

FTP

to use a different list command

debugdata set the data for the debug function
debugfunction set the debug function
dirlistonly return bare names when listing directories
dns_cache_timeout DNS cache timeout
dns_use_global_cache Non-zero value means to use the global dns cache
egdsocket Set to the Entropy Gathering Daemon socket pathname
encoding Set the Accept-Encoding string. Use this to tell a server you would like the response to be compressed.
errorbuffer Buffer to receive error messages in, must be at least CURL_ERROR_SIZE bytes big. If this is not used, error messages go to stderr instead:
failonerror no output on http error codes >= 300
file This is the FILE * or void * the regular output should be written to.
filetime Pass a long set to 1 to get the date of the requested document (if possible)! Pass a zero to shut it off.
fnmatch_data FNMATCH_FUNCTION user pointer
fnmatch_function Change match (fnmatch-like) callback for wildcard matching
followlocation use Location: Luke!
forbid_reuse Set to explicitly forbid the upcoming transfer's connection to be re-used when done. Do not use this unless you're absolutely sure of this, as it makes the operation slower and is less friendly for the network.
fresh_connect Set to explicitly use a new connection for the upcoming transfer. Do not use this unless you're absolutely sure of this, as it makes the operation slower and is less friendly for the network.
ftpport Set the FTP PORT string (interface name, named or numerical IP address) Use i.e '-' to use default address.
ftpsslauth When FTP over SSL/TLS is selected (with CURLOPT_USE_SSL), this option can be used to change libcurl's default action which is to first try "AUTH SSL" and then "AUTH TLS" in this order, and proceed when a OK response has been received.

Available parameters are: CURLFTPAUTH_DEFAULT - let libcurl decide CURLFTPAUTH_SSL - try "AUTH SSL" first, then TLS CURLFTPAUTH_TLS - try "AUTH TLS" first, then SSL

ftp_account zero terminated string for pass on to the FTP server when asked for "account" info
ftp_alternative_to_user Pointer to command string to send if USER/PASS fails.
ftp_create_missing_dirs FTP Option that causes missing dirs to be created on the remote server. In 7.19.4 we introduced the convenience enums for this option using the CURLFTP_CREATE_DIR prefix.
ftp_filemethod Select "file method" to use when doing FTP, see the curl_ftpmethod above.
ftp_response_timeout FTP option that changes the timeout, in seconds, associated with getting a response. This is different from transfer timeout time and essentially places a demand on the FTP server to acknowledge commands in a timely manner.
ftp_skip_pasv_ip Set to non-zero to skip the IP address received in a 227 PASV FTP server response. Typically used for FTP-SSL purposes but is not restricted to that. libcurl will then instead use the same IP address it used for the control connection.
ftp_ssl_ccc Send CCC (Clear Command Channel) after authentication
ftp_use_eprt Specifically switch on or off the FTP engine's use of the EPRT command ( it also disables the LPRT attempt). By default, those ones will always be attempted before the good old traditional PORT command.
ftp_use_epsv Specifically switch on or off the FTP engine's use of the EPSV command. By default, that one will always be attempted before the more traditional PASV command.
ftp_use_pret

FTP

send PRET before PASV

throw the header out too
headerdata convenient alias
headerfunction Function that will be called to store headers (instead of fwrite). The parameters will use fwrite() syntax, make sure to follow them.
http200aliases Set aliases for HTTP 200 in the HTTP Response header
httpauth Set this to a bitmask value to enable the particular authentications methods you like. Use this in combination with CURLOPT_USERPWD. Note that setting multiple bits may cause extra network round-trips.
httpget Set this to force the HTTP request to get back to GET. Only really usable if POST, PUT or a custom request have been used first.
httpheader This points to a linked list of headers, struct curl_slist kind
httppost This points to a linked list of post entries, struct curl_httppost
httpproxytunnel tunnel non-http operations through a HTTP proxy
http_content_decoding set to zero to disable the libcurl's decoding and thus pass the raw body data to the application even when it is encoded/compressed
http_transfer_decoding set to zero to disable the libcurl's decoding and thus pass the raw body data to the application even when it is encoded/compressed
http_version Specify which HTTP version to use! This must be set to one of the CURL_HTTP_VERSION* enums set below.
ignore_content_length ignore Content-Length
infile not used

Specified file stream to upload from (use as input):

infilesize If the CURLOPT_INFILE is used, this can be used to inform libcurl about how large the file being sent really is. That allows better error checking and better verifies that the upload was successful. -1 means unknown size.

For large file support, there is also a LARGE version of the key which takes an off_t type, allowing platforms with larger off_t sizes to handle larger files. See below for INFILESIZE_LARGE.

infilesize_large See the comment for INFILESIZE above, but in short, specifies the size of the file being uploaded. -1 means unknown.
interleavedata The stream to pass to INTERLEAVEFUNCTION.
interleavefunction Let the application define a custom write method for RTP data
intrface Set the interface string to use as outgoing network interface
ioctldata
ioctlfunction
ipresolve Set this option to one of the CURL_IPRESOLVE_* defines (see below) to tell libcurl to resolve names to those IP versions only. This only has affect on systems with support for more than one, i.e IPv4 and_ IPv6.
issuercert Issuer certificate
keypasswd password for the SSL or SSH private key
krblevel Set the krb4/5 security level, this also enables krb4/5 awareness. This is a string, 'clear', 'safe', 'confidential' or 'private'. If the string is set but doesn't match one of these, 'private' will be used.
lastentry the last unused
localport Local port number to bind the socket to
localportrange Number of ports to try, including the first one set with LOCALPORT. Thus, setting it to 1 will make no additional attempts but the first.
low_speed_limit If the download receives less than "low speed limit" bytes/second during "low speed time" seconds, the operations is aborted. You could i.e if you have a pretty high speed connection, abort if it is less than 2000 bytes/sec during 20 seconds.

Set the "low speed limit"

low_speed_time Set the "low speed time"
mail_from set the SMTP mail originator
mail_rcpt set the SMTP mail receiver(s)
maxconnects Max amount of cached alive connections
maxfilesize Set this option to limit the size of a file that will be downloaded from an HTTP or FTP server.

Note there is also LARGE version which adds large file support for platforms which have larger off_t sizes. See MAXFILESIZE_LARGE below.

maxfilesize_large Sets the maximum size of data that will be downloaded from an HTTP or FTP server. See MAXFILESIZE above for the LONG version.
maxredirs Maximum number of http redirects to follow
max_recv_speed_large If the connection proceeds too quickly then need to slow it down

limit-rate: maximum number of bytes per second to send or receive

max_send_speed_large If the connection proceeds too quickly then need to slow it down

limit-rate: maximum number of bytes per second to send or receive

netrc Specify whether to read the user+password from the .netrc or the URL. This must be one of the CURL_NETRC_* enums below.
netrc_file Set this option to the file name of your .netrc file you want libcurl to parse (using the CURLOPT_NETRC option). If not set, libcurl will do a poor attempt to find the user's home directory and check for a .netrc file in there.
new_directory_perms Permission used when creating new files and directories on the remote server for protocols that support it, SFTP/SCP/FILE
new_file_perms Permission used when creating new files and directories on the remote server for protocols that support it, SFTP/SCP/FILE
nobody use HEAD to get http document
noprogress shut off the progress meter
noproxy Comma separated list of hostnames defining no-proxy zones. These should match both hostnames directly, and hostnames within a domain. For example, local.com will match local.com and www.local.com, but NOT notlocal.com or www.notlocal.com. For compatibility with other implementations of this, .local.com will be considered to be the same as local.com. A single * is the only valid wildcard, and effectively disables the use of proxy.
nosignal Instruct libcurl to not use any signal/alarm handlers, even when using timeouts. This option is useful for multi-threaded applications. See libcurl-the-guide for more background information.
opensocketdata Callback function for opening socket (instead of socket(2)). Optionally, callback is able change the address or refuse to connect returning CURL_SOCKET_BAD. The callback should have type curl_opensocket_callback
opensocketfunction Callback function for opening socket (instead of socket(2)). Optionally, callback is able change the address or refuse to connect returning CURL_SOCKET_BAD. The callback should have type curl_opensocket_callback
password "name" and "pwd" to use when fetching.
port Port number to connect to, if other than default.
post HTTP POST method
postfields POST static input fields.
postfieldsize size of the POST input data, if strlen() is not good to use
postfieldsize_large The LARGE version of the standard POSTFIELDSIZE option
postquote send linked-list of post-transfer QUOTE commands
postredir Set the behaviour of POST when redirecting. Values must be set to one of CURL_REDIR* defines below. This used to be called CURLOPT_POST301
prequote send linked-list of pre-transfer QUOTE commands
private_opt Set pointer to private data
progressdata Data passed to the progress callback
progressfunction Function that will be called instead of the internal progress display function. This function should be defined as the curl_progress_callback prototype defines.
protocols set the bitmask for the protocols that are allowed to be used for the transfer, which thus helps the app which takes URLs from users or other external inputs and want to restrict what protocol(s) to deal with. Defaults to CURLPROTO_ALL.
proxy Name of proxy to use.
proxyauth Set this to a bitmask value to enable the particular authentications methods you like. Use this in combination with CURLOPT_PROXYUSERPWD. Note that setting multiple bits may cause extra network round-trips.
proxypassword "name" and "pwd" to use with Proxy when fetching.
proxyport Port of the proxy, can be set in the proxy string as well with: "[host]:[port]"
proxytype indicates type of proxy. accepted values are CURLPROXY_HTTP (default), CURLPROXY_SOCKS4, CURLPROXY_SOCKS4A and CURLPROXY_SOCKS5.
proxyusername "name" and "pwd" to use with Proxy when fetching.
proxyuserpwd "name:password" to use with proxy.
proxy_transfer_mode set transfer mode (;type=<a|i>) when doing FTP via an HTTP proxy
put HTTP PUT
quote send linked-list of QUOTE commands
random_file Set to a file name that contains random data for libcurl to use to seed the random engine when doing SSL connects.
range Range to get, specified as an ASCII string.
readdata convenient alias
readfunction Function that will be called to read the input (instead of fread). The parameters will use fread() syntax, make sure to follow them.
redir_protocols set the bitmask for the protocols that libcurl is allowed to follow to, as a subset of the CURLOPT_PROTOCOLS ones. That means the protocol needs to be set in both bitmasks to be allowed to get redirected to. Defaults to all protocols except FILE and SCP.
referer Set the referrer page (needed by some CGIs)
resolve send linked-list of name:port:address sets
resume_from Set the continuation offset.

Note there is also a LARGE version of this key which uses off_t types, allowing for large file offsets on platforms which use larger-than-32-bit off_t's. Look below for RESUME_FROM_LARGE.

resume_from_large Sets the continuation offset. There is also a LONG version of this; look above for RESUME_FROM.
rtspheader convenient alias
rtsp_client_cseq Manually initialize the client RTSP CSeq for this handle
rtsp_request RTSP request method (OPTIONS, SETUP, PLAY, etc...)
rtsp_server_cseq Manually initialize the server RTSP CSeq for this handle
rtsp_session_id The RTSP session identifier
rtsp_stream_uri The RTSP stream URI
rtsp_transport The Transport: header to use in RTSP requests
seekdata Callback function for seeking in the input stream
seekfunction Callback function for seeking in the input stream
share Provide a CURLShare for mutexing non-ts data
sockoptfunction callback function for setting socket options
socks5_gssapi_nec Socks Service
socks5_gssapi_service Socks Service
ssh_auth_types allowed SSH authentication methods
ssh_host_public_key_md5 used by scp/sftp to verify the host's public key
ssh_keydata set the SSH host key callback custom pointer
ssh_keyfunction set the SSH host key callback, must point to a curl_sshkeycallback function
ssh_knownhosts set the SSH knownhost file name to use
ssh_public_keyfile Used by scp/sftp to do public/private key authentication
sslcert name of the file keeping your private SSL-certificate
sslcerttype type of the file keeping your SSL-certificate ("DER", "PEM", "ENG")
sslengine crypto engine for the SSL-sub system
sslengine_default set the crypto engine for the SSL-sub system as default the param has no meaning...
sslkey name of the file keeping your private SSL-key
sslkeytype type of the file keeping your private SSL-key ("DER", "PEM", "ENG")
sslversion What version to specifically try to use. See CURL_SSLVERSION defines below.
ssl_cipher_list Specify which SSL ciphers to use
ssl_ctx_data Set the userdata for the ssl context callback function's third argument
ssl_ctx_function Set the ssl context callback function, currently only for OpenSSL ssl_ctx in second argument. The function must be matching the curl_ssl_ctx_callback proto.
ssl_sessionid_cache set to 0 to disable session ID re-use for this transfer, default is enabled (== 1)
ssl_verifyhost Set if we should verify the Common name from the peer certificate in ssl handshake, set 1 to check existence, 2 to ensure that it matches the provided hostname.
ssl_verifypeer Set if we should verify the peer in ssl handshake, set 1 to verify.
stderr HTTP request, for odd commands like DELETE, TRACE and others
tcp_nodelay Enable/disable the TCP Nagle algorithm
telnetoptions This points to a linked list of telnet options
tftp_blksize block size for TFTP transfers
timecondition What kind of HTTP time condition to use, see defines
timeout Time-out the read operation after this amount of seconds
timeout_ms Same as TIMEOUT and CONNECTTIMEOUT, but with ms resolution
timevalue Time to use with the above condition. Specified in number of seconds since 1 Jan 1970
tlsauth_password Set a password for authenticated TLS
tlsauth_type Set authentication type for authenticated TLS
tlsauth_username Set a username for authenticated TLS
transfertext transfer data in text/ASCII format
unrestricted_auth Continue to send authentication (user+password) when following locations, even when hostname changed. This can potentially send off the name and password to whatever host the server decides.
upload this is an upload
url The full URL to get/put
useragent Set the User-Agent string (examined by some CGIs)
username "name" and "pwd" to use when fetching.
userpwd "name:password" to use when fetching.
use_ssl Enable SSL/TLS for FTP, pick one of: CURLFTPSSL_TRY - try using SSL, proceed anyway otherwise CURLFTPSSL_CONTROL - SSL for the control connection or fail CURLFTPSSL_ALL - SSL for all communication or fail
verbose talk a lot
wildcardmatch Turn on wildcard matching
writedata convenient alias
writefunction Function that will be called to store the output (instead of fwrite). The parameters will use fwrite() syntax, make sure to follow them.
writeheader send FILE * or void * to store headers to, if you use a callback it is simply passed to the callback unmodified
writeinfo Pass a pointer to string of the output using full variable-replacement as described elsewhere.

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