curl_easy_setopt(3) set options for a curl easy handle

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLoption option, parameter);

DESCRIPTION

curl_easy_setopt(3) is used to tell libcurl how to behave. By setting the appropriate options, the application can change libcurl's behavior. All options are set with an option followed by a parameter. That parameter can be a long, a function pointer, an object pointer or a curl_off_t, depending on what the specific option expects. Read this manual carefully as bad input values may cause libcurl to behave badly! You can only set one option in each function call. A typical application uses many curl_easy_setopt(3) calls in the setup phase.

Options set with this function call are valid for all forthcoming transfers performed using this handle. The options are not in any way reset between transfers, so if you want subsequent transfers with different options, you must change them between the transfers. You can optionally reset all options back to internal default with curl_easy_reset(3).

Strings passed to libcurl as 'char *' arguments, are copied by the library; thus the string storage associated to the pointer argument may be overwritten after curl_easy_setopt(3) returns. The only exception to this rule is really CURLOPT_POSTFIELDS(3), but the alternative that copies the string CURLOPT_COPYPOSTFIELDS(3) has some usage characteristics you need to read up on.

The order in which the options are set does not matter.

Before version 7.17.0, strings were not copied. Instead the user was forced keep them available until libcurl no longer needed them.

The handle is the return code from a curl_easy_init(3) or curl_easy_duphandle(3) call.

BEHAVIOR OPTIONS

CURLOPT_VERBOSE
Display verbose information. See CURLOPT_VERBOSE(3)
CURLOPT_HEADER
Include the header in the body output. See CURLOPT_HEADER(3)
CURLOPT_NOPROGRESS
Shut off the progress meter. See CURLOPT_NOPROGRESS(3)
CURLOPT_NOSIGNAL
Do not install signal handlers. See CURLOPT_NOSIGNAL(3)
CURLOPT_WILDCARDMATCH
Transfer multiple files according to a file name pattern. See CURLOPT_WILDCARDMATCH(3)

CALLBACK OPTIONS

CURLOPT_WRITEFUNCTION
Callback for writing data. See CURLOPT_WRITEFUNCTION(3)
CURLOPT_WRITEDATA
Data pointer to pass to the write callback. See CURLOPT_WRITEDATA(3)
CURLOPT_READFUNCTION
Callback for reading data. See CURLOPT_READFUNCTION(3)
CURLOPT_READDATA
Data pointer to pass to the read callback. See CURLOPT_READDATA(3)
CURLOPT_IOCTLFUNCTION
Callback for I/O operations. See CURLOPT_IOCTLFUNCTION(3)
CURLOPT_IOCTLDATA
Data pointer to pass to the I/O callback. See CURLOPT_IOCTLDATA(3)
CURLOPT_SEEKFUNCTION
Callback for seek operations. See CURLOPT_SEEKFUNCTION(3)
CURLOPT_SEEKDATA
Data pointer to pass to the seek callback. See CURLOPT_SEEKDATA(3)
CURLOPT_SOCKOPTFUNCTION
Callback for sockopt operations. See CURLOPT_SOCKOPTFUNCTION(3)
CURLOPT_SOCKOPTDATA
Data pointer to pass to the sockopt callback. See CURLOPT_SOCKOPTDATA(3)
CURLOPT_OPENSOCKETFUNCTION
Callback for socket creation. See CURLOPT_OPENSOCKETFUNCTION(3)
CURLOPT_OPENSOCKETDATA
Data pointer to pass to the open socket callback. See CURLOPT_OPENSOCKETDATA(3)
CURLOPT_CLOSESOCKETFUNCTION
Callback for closing socket. See CURLOPT_CLOSESOCKETFUNCTION(3)
CURLOPT_CLOSESOCKETDATA
Data pointer to pass to the close socket callback. See CURLOPT_CLOSESOCKETDATA(3)
CURLOPT_PROGRESSFUNCTION
OBSOLETE callback for progress meter. See CURLOPT_PROGRESSFUNCTION(3)
CURLOPT_PROGRESSDATA
Data pointer to pass to the progress meter callback. See CURLOPT_PROGRESSDATA(3)
CURLOPT_XFERINFOFUNCTION
Callback for progress meter. See CURLOPT_XFERINFOFUNCTION(3)
CURLOPT_XFERINFODATA
Data pointer to pass to the progress meter callback. See CURLOPT_XFERINFODATA(3)
CURLOPT_HEADERFUNCTION
Callback for writing received headers. See CURLOPT_HEADERFUNCTION(3)
CURLOPT_HEADERDATA
Data pointer to pass to the header callback. See CURLOPT_HEADERDATA(3)
CURLOPT_DEBUGFUNCTION
Callback for debug information. See CURLOPT_DEBUGFUNCTION(3)
CURLOPT_DEBUGDATA
Data pointer to pass to the debug callback. See CURLOPT_DEBUGDATA(3)
CURLOPT_SSL_CTX_FUNCTION
Callback for SSL context logic. See CURLOPT_SSL_CTX_FUNCTION(3)
CURLOPT_SSL_CTX_DATA
Data pointer to pass to the SSL context callback. See CURLOPT_SSL_CTX_DATA(3)
CURLOPT_CONV_TO_NETWORK_FUNCTION
Callback for code base conversion. See CURLOPT_CONV_TO_NETWORK_FUNCTION(3)
CURLOPT_CONV_FROM_NETWORK_FUNCTION
Callback for code base conversion. See CURLOPT_CONV_FROM_NETWORK_FUNCTION(3)
CURLOPT_CONV_FROM_UTF8_FUNCTION
Callback for code base conversion. See CURLOPT_CONV_FROM_UTF8_FUNCTION(3)
CURLOPT_INTERLEAVEFUNCTION
Callback for RTSP interleaved data. See CURLOPT_INTERLEAVEFUNCTION(3)
CURLOPT_INTERLEAVEDATA
Data pointer to pass to the RTSP interleave callback. See CURLOPT_INTERLEAVEDATA(3)
CURLOPT_CHUNK_BGN_FUNCTION
Callback for wildcard download start of chunk. See CURLOPT_CHUNK_BGN_FUNCTION(3)
CURLOPT_CHUNK_END_FUNCTION
Callback for wildcard download end of chunk. See CURLOPT_CHUNK_END_FUNCTION(3)
CURLOPT_CHUNK_DATA
Data pointer to pass to the chunk callbacks. See CURLOPT_CHUNK_DATA(3)
CURLOPT_FNMATCH_FUNCTION
Callback for wildcard matching. See CURLOPT_FNMATCH_FUNCTION(3)
CURLOPT_FNMATCH_DATA
Data pointer to pass to the wildcard matching callback. See CURLOPT_FNMATCH_DATA(3)

ERROR OPTIONS

CURLOPT_ERRORBUFFER
Error message buffer. See CURLOPT_ERRORBUFFER(3)
CURLOPT_STDERR
stderr replacement stream. See CURLOPT_STDERR(3)
CURLOPT_FAILONERROR
Fail on HTTP 4xx errors. CURLOPT_FAILONERROR(3)

NETWORK OPTIONS

CURLOPT_URL
URL to work on. See CURLOPT_URL(3)
CURLOPT_PATH_AS_IS
Disable squashing /../ and /./ sequences in the path. See CURLOPT_PATH_AS_IS(3)
CURLOPT_PROTOCOLS
Allowed protocols. See CURLOPT_PROTOCOLS(3)
CURLOPT_REDIR_PROTOCOLS
Protocols to allow redirects to. See CURLOPT_REDIR_PROTOCOLS(3)
CURLOPT_DEFAULT_PROTOCOL
Default protocol. See CURLOPT_DEFAULT_PROTOCOL(3)
CURLOPT_PROXY
Proxy to use. See CURLOPT_PROXY(3)
CURLOPT_PROXYPORT
Proxy port to use. See CURLOPT_PROXYPORT(3)
CURLOPT_PROXYTYPE
Proxy type. See CURLOPT_PROXYTYPE(3)
CURLOPT_NOPROXY
Filter out hosts from proxy use. CURLOPT_NOPROXY(3)
CURLOPT_HTTPPROXYTUNNEL
Tunnel through the HTTP proxy. CURLOPT_HTTPPROXYTUNNEL(3)
CURLOPT_SOCKS5_GSSAPI_SERVICE
Socks5 GSSAPI service name. CURLOPT_SOCKS5_GSSAPI_SERVICE(3)
CURLOPT_SOCKS5_GSSAPI_NEC
Socks5 GSSAPI NEC mode. See CURLOPT_SOCKS5_GSSAPI_NEC(3)
CURLOPT_PROXY_SERVICE_NAME
Proxy service name. CURLOPT_PROXY_SERVICE_NAME(3)
CURLOPT_SERVICE_NAME
SPNEGO service name. CURLOPT_SERVICE_NAME(3)
CURLOPT_INTERFACE
Bind connection locally to this. See CURLOPT_INTERFACE(3)
CURLOPT_LOCALPORT
Bind connection locally to this port. See CURLOPT_LOCALPORT(3)
CURLOPT_LOCALPORTRANGE
Bind connection locally to port range. See CURLOPT_LOCALPORTRANGE(3)
CURLOPT_DNS_CACHE_TIMEOUT
Timeout for DNS cache. See CURLOPT_DNS_CACHE_TIMEOUT(3)
CURLOPT_DNS_USE_GLOBAL_CACHE
OBSOLETE Enable global DNS cache. See CURLOPT_DNS_USE_GLOBAL_CACHE(3)
CURLOPT_BUFFERSIZE
Ask for smaller buffer size. See CURLOPT_BUFFERSIZE(3)
CURLOPT_PORT
Port number to connect to. See CURLOPT_PORT(3)
CURLOPT_TCP_NODELAY
Disable the Nagle algorithm. See CURLOPT_TCP_NODELAY(3)
CURLOPT_ADDRESS_SCOPE
IPv6 scope for local addresses. See CURLOPT_ADDRESS_SCOPE(3)
CURLOPT_TCP_KEEPALIVE
Enable TCP keep-alive. See CURLOPT_TCP_KEEPALIVE(3)
CURLOPT_TCP_KEEPIDLE
Idle time before sending keep-alive. See CURLOPT_TCP_KEEPIDLE(3)
CURLOPT_TCP_KEEPINTVL
Interval between keep-alive probes. See CURLOPT_TCP_KEEPINTVL(3)
CURLOPT_UNIX_SOCKET_PATH
Path to a Unix domain socket. See CURLOPT_UNIX_SOCKET_PATH(3)

NAMES and PASSWORDS OPTIONS (Authentication)

CURLOPT_NETRC
Enable .netrc parsing. See CURLOPT_NETRC(3)
CURLOPT_NETRC_FILE
.netrc file name. See CURLOPT_NETRC_FILE(3)
CURLOPT_USERPWD
User name and password. See CURLOPT_USERPWD(3)
CURLOPT_PROXYUSERPWD
Proxy user name and password. See CURLOPT_PROXYUSERPWD(3)
CURLOPT_USERNAME
User name. See CURLOPT_USERNAME(3)
CURLOPT_PASSWORD
Password. See CURLOPT_PASSWORD(3)
CURLOPT_LOGIN_OPTIONS
Login options. See CURLOPT_LOGIN_OPTIONS(3)
CURLOPT_PROXYUSERNAME
Proxy user name. See CURLOPT_PROXYUSERNAME(3)
CURLOPT_PROXYPASSWORD
Proxy password. See CURLOPT_PROXYPASSWORD(3)
CURLOPT_HTTPAUTH
HTTP server authentication methods. See CURLOPT_HTTPAUTH(3)
CURLOPT_TLSAUTH_USERNAME
TLS authentication user name. See CURLOPT_TLSAUTH_USERNAME(3)
CURLOPT_TLSAUTH_PASSWORD
TLS authentication password. See CURLOPT_TLSAUTH_PASSWORD(3)
CURLOPT_TLSAUTH_TYPE
TLS authentication methods. See CURLOPT_TLSAUTH_TYPE(3)
CURLOPT_PROXYAUTH
HTTP proxy authentication methods. See CURLOPT_PROXYAUTH(3)
CURLOPT_SASL_IR
Enable SASL initial response. See CURLOPT_SASL_IR(3)
CURLOPT_XOAUTH2_BEARER
OAuth2 bearer token. See CURLOPT_XOAUTH2_BEARER(3)

HTTP OPTIONS

CURLOPT_AUTOREFERER
Automatically set Referer: header. See CURLOPT_AUTOREFERER(3)
CURLOPT_ACCEPT_ENCODING
Accept-Encoding and automatic decompressing data. See CURLOPT_ACCEPT_ENCODING(3)
CURLOPT_TRANSFER_ENCODING
Request Transfer-Encoding. See CURLOPT_TRANSFER_ENCODING(3)
CURLOPT_FOLLOWLOCATION
Follow HTTP redirects. See CURLOPT_FOLLOWLOCATION(3)
CURLOPT_UNRESTRICTED_AUTH
Do not restrict authentication to original host. CURLOPT_UNRESTRICTED_AUTH(3)
CURLOPT_MAXREDIRS
Maximum number of redirects to follow. See CURLOPT_MAXREDIRS(3)
CURLOPT_POSTREDIR
How to act on redirects after POST. See CURLOPT_POSTREDIR(3)
CURLOPT_PUT
Issue a HTTP PUT request. See CURLOPT_PUT(3)
CURLOPT_POST
Issue a HTTP POST request. See CURLOPT_POST(3)
CURLOPT_POSTFIELDS
Send a POST with this data. See CURLOPT_POSTFIELDS(3)
CURLOPT_POSTFIELDSIZE
The POST data is this big. See CURLOPT_POSTFIELDSIZE(3)
CURLOPT_POSTFIELDSIZE_LARGE
The POST data is this big. See CURLOPT_POSTFIELDSIZE_LARGE(3)
CURLOPT_COPYPOSTFIELDS
Send a POST with this data - and copy it. See CURLOPT_COPYPOSTFIELDS(3)
CURLOPT_HTTPPOST
Multipart formpost HTTP POST. See CURLOPT_HTTPPOST(3)
CURLOPT_REFERER
Referer: header. See CURLOPT_REFERER(3)
CURLOPT_USERAGENT
User-Agent: header. See CURLOPT_USERAGENT(3)
CURLOPT_HTTPHEADER
Custom HTTP headers. See CURLOPT_HTTPHEADER(3)
CURLOPT_HEADEROPT
Control custom headers. See CURLOPT_HEADEROPT(3)
CURLOPT_PROXYHEADER
Custom HTTP headers sent to proxy. See CURLOPT_PROXYHEADER(3)
CURLOPT_HTTP200ALIASES
Alternative versions of 200 OK. See CURLOPT_HTTP200ALIASES(3)
CURLOPT_COOKIE
Cookie(s) to send. See CURLOPT_COOKIE(3)
CURLOPT_COOKIEFILE
File to read cookies from. See CURLOPT_COOKIEFILE(3)
CURLOPT_COOKIEJAR
File to write cookies to. See CURLOPT_COOKIEJAR(3)
CURLOPT_COOKIESESSION
Start a new cookie session. See CURLOPT_COOKIESESSION(3)
CURLOPT_COOKIELIST
Add or control cookies. See CURLOPT_COOKIELIST(3)
CURLOPT_HTTPGET
Do a HTTP GET request. See CURLOPT_HTTPGET(3)
CURLOPT_HTTP_VERSION
HTTP version to use. CURLOPT_HTTP_VERSION(3)
CURLOPT_IGNORE_CONTENT_LENGTH
Ignore Content-Length. See CURLOPT_IGNORE_CONTENT_LENGTH(3)
CURLOPT_HTTP_CONTENT_DECODING
Disable Content decoding. See CURLOPT_HTTP_CONTENT_DECODING(3)
CURLOPT_HTTP_TRANSFER_DECODING
Disable Transfer decoding. See CURLOPT_HTTP_TRANSFER_DECODING(3)
CURLOPT_EXPECT_100_TIMEOUT_MS
100-continue timeout. See CURLOPT_EXPECT_100_TIMEOUT_MS(3)
CURLOPT_PIPEWAIT
Wait on connection to pipeline on it. See CURLOPT_PIPEWAIT(3)
CURLOPT_STREAM_DEPENDS
This HTTP/2 stream depends on another. See CURLOPT_STREAM_DEPENDS(3)
CURLOPT_STREAM_DEPENDS_E
This HTTP/2 stream depends on another exclusively. See CURLOPT_STREAM_DEPENDS_E(3)
CURLOPT_STREAM_WEIGHT
Set this HTTP/2 stream's weight. See CURLOPT_STREAM_WEIGHT(3)

SMTP OPTIONS

CURLOPT_MAIL_FROM
Address of the sender. See CURLOPT_MAIL_FROM(3)
CURLOPT_MAIL_RCPT
Address of the recipients. See CURLOPT_MAIL_RCPT(3)
CURLOPT_MAIL_AUTH
Authentication address. See CURLOPT_MAIL_AUTH(3)

TFTP OPTIONS

CURLOPT_TFTP_BLKSIZE
TFTP block size. See CURLOPT_TFTP_BLKSIZE(3)

FTP OPTIONS

CURLOPT_FTPPORT
Use active FTP. See CURLOPT_FTPPORT(3)
CURLOPT_QUOTE
Commands to run before transfer. See CURLOPT_QUOTE(3)
CURLOPT_POSTQUOTE
Commands to run after transfer. See CURLOPT_POSTQUOTE(3)
CURLOPT_PREQUOTE
Commands to run just before transfer. See CURLOPT_PREQUOTE(3)
CURLOPT_APPEND
Append to remote file. See CURLOPT_APPEND(3)
CURLOPT_FTP_USE_EPRT
Use EPTR. See CURLOPT_FTP_USE_EPRT(3)
CURLOPT_FTP_USE_EPSV
Use EPSV. See CURLOPT_FTP_USE_EPSV(3)
CURLOPT_FTP_USE_PRET
Use PRET. See CURLOPT_FTP_USE_PRET(3)
CURLOPT_FTP_CREATE_MISSING_DIRS
Create missing directories on the remote server. See CURLOPT_FTP_CREATE_MISSING_DIRS(3)
CURLOPT_FTP_RESPONSE_TIMEOUT
Timeout for FTP responses. See CURLOPT_FTP_RESPONSE_TIMEOUT(3)
CURLOPT_FTP_ALTERNATIVE_TO_USER
Alternative to USER. See CURLOPT_FTP_ALTERNATIVE_TO_USER(3)
CURLOPT_FTP_SKIP_PASV_IP
Ignore the IP address in the PASV response. See CURLOPT_FTP_SKIP_PASV_IP(3)
CURLOPT_FTPSSLAUTH
Control how to do TLS. See CURLOPT_FTPSSLAUTH(3)
CURLOPT_FTP_SSL_CCC
Back to non-TLS again after authentication. See CURLOPT_FTP_SSL_CCC(3)
CURLOPT_FTP_ACCOUNT
Send ACCT command. See CURLOPT_FTP_ACCOUNT(3)
CURLOPT_FTP_FILEMETHOD
Specify how to reach files. See CURLOPT_FTP_FILEMETHOD(3)

RTSP OPTIONS

CURLOPT_RTSP_REQUEST
RTSP request. See CURLOPT_RTSP_REQUEST(3)
CURLOPT_RTSP_SESSION_ID
RTSP session-id. See CURLOPT_RTSP_SESSION_ID(3)
CURLOPT_RTSP_STREAM_URI
RTSP stream URI. See CURLOPT_RTSP_STREAM_URI(3)
CURLOPT_RTSP_TRANSPORT
RTSP Transport: header. See CURLOPT_RTSP_TRANSPORT(3)
CURLOPT_RTSP_CLIENT_CSEQ
Client CSEQ number. See CURLOPT_RTSP_CLIENT_CSEQ(3)
CURLOPT_RTSP_SERVER_CSEQ
CSEQ number for RTSP Server->Client request. See CURLOPT_RTSP_SERVER_CSEQ(3)

PROTOCOL OPTIONS

CURLOPT_TRANSFERTEXT
Use text transfer. See CURLOPT_TRANSFERTEXT(3)
CURLOPT_PROXY_TRANSFER_MODE
Add transfer mode to URL over proxy. See CURLOPT_PROXY_TRANSFER_MODE(3)
CURLOPT_CRLF
Convert newlines. See CURLOPT_CRLF(3)
CURLOPT_RANGE
Range requests. See CURLOPT_RANGE(3)
CURLOPT_RESUME_FROM
Resume a transfer. See CURLOPT_RESUME_FROM(3)
CURLOPT_RESUME_FROM_LARGE
Resume a transfer. See CURLOPT_RESUME_FROM_LARGE(3)
CURLOPT_CUSTOMREQUEST
Custom request/method. See CURLOPT_CUSTOMREQUEST(3)
CURLOPT_FILETIME
Request file modification date and time. See CURLOPT_FILETIME(3)
CURLOPT_DIRLISTONLY
List only. See CURLOPT_DIRLISTONLY(3)
CURLOPT_NOBODY
Do not get the body contents. See CURLOPT_NOBODY(3)
CURLOPT_INFILESIZE
Size of file to send. CURLOPT_INFILESIZE(3)
CURLOPT_INFILESIZE_LARGE
Size of file to send. CURLOPT_INFILESIZE_LARGE(3)
CURLOPT_UPLOAD
Upload data. See CURLOPT_UPLOAD(3)
CURLOPT_MAXFILESIZE
Maximum file size to get. See CURLOPT_MAXFILESIZE(3)
CURLOPT_MAXFILESIZE_LARGE
Maximum file size to get. See CURLOPT_MAXFILESIZE_LARGE(3)
CURLOPT_TIMECONDITION
Make a time conditional request. See CURLOPT_TIMECONDITION(3)
CURLOPT_TIMEVALUE
Time value for the time conditional request. See CURLOPT_TIMEVALUE(3)

CONNECTION OPTIONS

CURLOPT_TIMEOUT
Timeout for the entire request. See CURLOPT_TIMEOUT(3)
CURLOPT_TIMEOUT_MS
Millisecond timeout for the entire request. See CURLOPT_TIMEOUT_MS(3)
CURLOPT_LOW_SPEED_LIMIT
Low speed limit to abort transfer. See CURLOPT_LOW_SPEED_LIMIT(3)
CURLOPT_LOW_SPEED_TIME
Time to be below the speed to trigger low speed abort. See CURLOPT_LOW_SPEED_TIME(3)
CURLOPT_MAX_SEND_SPEED_LARGE
Cap the upload speed to this. See CURLOPT_MAX_SEND_SPEED_LARGE(3)
CURLOPT_MAX_RECV_SPEED_LARGE
Cap the download speed to this. See CURLOPT_MAX_RECV_SPEED_LARGE(3)
CURLOPT_MAXCONNECTS
Maximum number of connections in the connection pool. See CURLOPT_MAXCONNECTS(3)
CURLOPT_FRESH_CONNECT
Use a new connection. CURLOPT_FRESH_CONNECT(3)
CURLOPT_FORBID_REUSE
Prevent subsequent connections from re-using this. See CURLOPT_FORBID_REUSE(3)
CURLOPT_CONNECTTIMEOUT
Timeout for the connection phase. See CURLOPT_CONNECTTIMEOUT(3)
CURLOPT_CONNECTTIMEOUT_MS
Millisecond timeout for the connection phase. See CURLOPT_CONNECTTIMEOUT_MS(3)
CURLOPT_IPRESOLVE
IP version to resolve to. See CURLOPT_IPRESOLVE(3)
CURLOPT_CONNECT_ONLY
Only connect, nothing else. See CURLOPT_CONNECT_ONLY(3)
CURLOPT_USE_SSL
Use TLS/SSL. See CURLOPT_USE_SSL(3)
CURLOPT_RESOLVE
Provide fixed/fake name resolves. See CURLOPT_RESOLVE(3)
CURLOPT_DNS_INTERFACE
Bind name resolves to this interface. See CURLOPT_DNS_INTERFACE(3)
CURLOPT_DNS_LOCAL_IP4
Bind name resolves to this IP4 address. See CURLOPT_DNS_LOCAL_IP4(3)
CURLOPT_DNS_LOCAL_IP6
Bind name resolves to this IP6 address. See CURLOPT_DNS_LOCAL_IP6(3)
CURLOPT_DNS_SERVERS
Preferred DNS servers. See CURLOPT_DNS_SERVERS(3)
CURLOPT_ACCEPTTIMEOUT_MS
Timeout for waiting for the server's connect back to be accepted. See CURLOPT_ACCEPTTIMEOUT_MS(3)

SSL and SECURITY OPTIONS

CURLOPT_SSLCERT
Client cert. See CURLOPT_SSLCERT(3)
CURLOPT_SSLCERTTYPE
Client cert type. See CURLOPT_SSLCERTTYPE(3)
CURLOPT_SSLKEY
Client key. See CURLOPT_SSLKEY(3)
CURLOPT_SSLKEYTYPE
Client key type. See CURLOPT_SSLKEYTYPE(3)
CURLOPT_KEYPASSWD
Client key password. See CURLOPT_KEYPASSWD(3)
CURLOPT_SSL_ENABLE_ALPN
Enable use of ALPN. See CURLOPT_SSL_ENABLE_ALPN(3)
CURLOPT_SSL_ENABLE_NPN
Enable use of NPN. See CURLOPT_SSL_ENABLE_NPN(3)
CURLOPT_SSLENGINE
Use identifier with SSL engine. See CURLOPT_SSLENGINE(3)
CURLOPT_SSLENGINE_DEFAULT
Default SSL engine. See CURLOPT_SSLENGINE_DEFAULT(3)
CURLOPT_SSL_FALSESTART
Enable TLS False Start. See CURLOPT_SSL_FALSESTART(3)
CURLOPT_SSLVERSION
SSL version to use. See CURLOPT_SSLVERSION(3)
CURLOPT_SSL_VERIFYHOST
Verify the host name in the SSL certificate. See CURLOPT_SSL_VERIFYHOST(3)
CURLOPT_SSL_VERIFYPEER
Verify the SSL certificate. See CURLOPT_SSL_VERIFYPEER(3)
CURLOPT_SSL_VERIFYSTATUS
Verify the SSL certificate's status. See CURLOPT_SSL_VERIFYSTATUS(3)
CURLOPT_CAINFO
CA cert bundle. See CURLOPT_CAINFO(3)
CURLOPT_ISSUERCERT
Issuer certificate. See CURLOPT_ISSUERCERT(3)
CURLOPT_CAPATH
Path to CA cert bundle. See CURLOPT_CAPATH(3)
CURLOPT_CRLFILE
Certificate Revocation List. See CURLOPT_CRLFILE(3)
CURLOPT_CERTINFO
Extract certificate info. See CURLOPT_CERTINFO(3)
CURLOPT_PINNEDPUBLICKEY
Set pinned SSL public key . See CURLOPT_PINNEDPUBLICKEY(3)
CURLOPT_RANDOM_FILE
Provide source for entropy random data. See CURLOPT_RANDOM_FILE(3)
CURLOPT_EGDSOCKET
Identify EGD socket for entropy. See CURLOPT_EGDSOCKET(3)
CURLOPT_SSL_CIPHER_LIST
Ciphers to use. See CURLOPT_SSL_CIPHER_LIST(3)
CURLOPT_SSL_SESSIONID_CACHE
Disable SSL session-id cache. See CURLOPT_SSL_SESSIONID_CACHE(3)
CURLOPT_SSL_OPTIONS
Control SSL behavior. See CURLOPT_SSL_OPTIONS(3)
CURLOPT_KRBLEVEL
Kerberos security level. See CURLOPT_KRBLEVEL(3)
CURLOPT_GSSAPI_DELEGATION
Disable GSS-API delegation. See CURLOPT_GSSAPI_DELEGATION(3)

SSH OPTIONS

CURLOPT_SSH_AUTH_TYPES
SSH authentication types. See CURLOPT_SSH_AUTH_TYPES(3)
CURLOPT_SSH_HOST_PUBLIC_KEY_MD5
MD5 of host's public key. See CURLOPT_SSH_HOST_PUBLIC_KEY_MD5(3)
CURLOPT_SSH_PUBLIC_KEYFILE
File name of public key. See CURLOPT_SSH_PUBLIC_KEYFILE(3)
CURLOPT_SSH_PRIVATE_KEYFILE
File name of private key. See CURLOPT_SSH_PRIVATE_KEYFILE(3)
CURLOPT_SSH_KNOWNHOSTS
File name with known hosts. See CURLOPT_SSH_KNOWNHOSTS(3)
CURLOPT_SSH_KEYFUNCTION
Callback for known hosts handling. See CURLOPT_SSH_KEYFUNCTION(3)
CURLOPT_SSH_KEYDATA
Custom pointer to pass to ssh key callback. See CURLOPT_SSH_KEYDATA(3)

OTHER OPTIONS

CURLOPT_PRIVATE
Private pointer to store. See CURLOPT_PRIVATE(3)
CURLOPT_SHARE
Share object to use. See CURLOPT_SHARE(3)
CURLOPT_NEW_FILE_PERMS
Mode for creating new remote files. See CURLOPT_NEW_FILE_PERMS(3)
CURLOPT_NEW_DIRECTORY_PERMS
Mode for creating new remote directories. See CURLOPT_NEW_DIRECTORY_PERMS(3)

TELNET OPTIONS

CURLOPT_TELNETOPTIONS
TELNET options. See CURLOPT_TELNETOPTIONS(3)

RETURN VALUE

CURLE_OK (zero) means that the option was set properly, non-zero means an error occurred as <curl/curl.h> defines. See the libcurl-errors(3) man page for the full list with descriptions.

If you try to set an option that libcurl doesn't know about, perhaps because the library is too old to support it or the option was removed in a recent version, this function will return CURLE_UNKNOWN_OPTION. If support for the option was disabled at compile-time, it will return CURLE_NOT_BUILT_IN.

EXAMPLE

CURL *curl = curl_easy_init();
if(curl) {
  CURLcode res;
  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
  res = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}