The Linux Manuals (man pages) document is an important part of Linux documents. Linux Manuals are organized as several sections. Each section has a group of commands for a specific area in Linux usage, administration or development.
CURLOPT_TCP_KEEPALIVE – enable TCP keep-alive probing Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPALIVE, long probe); DescriptionPass a long. If set to 1, TCP keepalive probes will be sent. The delay and frequency of these probes can be controlled by the CURLOPT_TCP_KEEPIDLE(3) and CURLOPT_TCP_KEEPINTVL(3) options, provided the operating system supports them. Set to 0 (default behavior) to…
CURLOPT_STDERR – redirect stderr to another stream Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STDERR, FILE *stream); DescriptionPass a FILE * as parameter. Tell libcurl to use this stream instead of stderr when showing the progress meter and displaying CURLOPT_VERBOSE(3) data. Defaultstderr ProtocolsAll ExampleTODO AvailabilityAlways Return ValueReturns CURLE_OK See AlsoCURLOPT_VERBOSE(3), CURLOPT_NOPROGRESS(3),
CURLOPT_SSL_VERIFYPEER – verify the peer’s SSL certificate Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYPEER, long verify); DescriptionPass a long as parameter to enable or disable. This option determines whether curl verifies the authenticity of the peer’s certificate. A value of 1 means curl verifies; 0 (zero) means it doesn’t. When negotiating a TLS or SSL connection,…
CURLOPT_SSL_VERIFYHOST – verify the certificate’s name against host Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYHOST, long verify); DescriptionPass a long as parameter specifying what to verify. This option determines whether libcurl verifies that the server cert is for the server it is known as. When negotiating TLS and SSL connections, the server sends a certificate indicating…
CURLOPT_SSL_SESSIONID_CACHE – enable/disable use of the SSL session-ID cache Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_SESSIONID_CACHE, long enabled);DescriptionPass a long set to 0 to disable libcurl’s use of SSL session-ID caching. Set this to 1 to enable it. By default all transfers are done using the cache enabled. While nothing ever should get hurt by attempting…
CURLOPT_SSL_OPTIONS – set SSL behavior options Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_OPTIONS, long bitmask); DescriptionPass a long with a bitmask to tell libcurl about specific SSL behaviors. CURLSSLOPT_ALLOW_BEAST is the only supported bit and by setting this the user will tell libcurl to not attempt to use any workarounds for a security flaw in the…
CURLOPT_SSL_ENABLE_NPN – enable NPN Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_NPN, long npn); DescriptionPass a long as parameter, 0 or 1 where 1 is for enable and 0 for disable. This option enables/disables NPN in the SSL handshake (if the SSL backend libcurl is built to use supports it), which can be used to negotiate http2….
CURLOPT_SSL_ENABLE_ALPN – enable ALPN Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_ENABLE_ALPN, long npn); DescriptionPass a long as parameter, 0 or 1 where 1 is for enable and 0 for disable. This option enables/disables ALPN in the SSL handshake (if the SSL backend libcurl is built to use supports it), which can be used to negotiate http2….
CURLOPT_SSL_CTX_FUNCTION – openssl specific callback to do SSL magic Synopsis#include <curl/curl.h> CURLcode ssl_ctx_callback(CURL *curl, void *ssl_ctx, void *userptr); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CTX_FUNCTION, ssl_ctx_callback);DescriptionThis option only works for libcurl powered by OpenSSL. If libcurl was built against another SSL library, this functionality is absent. Pass a pointer to your callback function, which should match the prototype…
CURLOPT_SSL_CTX_DATA – custom pointer passed to ssl_ctx callback Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CTX_DATA, void *pointer); DescriptionData pointer to pass to the ssl context callback set by the option CURLOPT_SSL_CTX_FUNCTION(3), this is the pointer you’ll get as third parameter. DefaultNULL ProtocolsAll TLS based protocols: HTTPS, FTPS, IMAPS, POP3, SMTPS etc. ExampleTODO AvailabilityAdded in 7.11.0. Only…
CURLOPT_SSL_CIPHER_LIST – specify ciphers to use for TLS Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CIPHER_LIST, char *list); DescriptionPass a char *, pointing to a zero terminated string holding the list of ciphers to use for the SSL connection. The list must be syntactically correct, it consists of one or more cipher strings separated by colons. Commas…
CURLOPT_SSLVERSION – set preferred TLS/SSL version Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLVERSION, long version); DescriptionPass a long as parameter to control which version of SSL/TLS to attempt to use. Use one of the available defines for this purpose. The available options are: CURL_SSLVERSION_DEFAULT The default action. This will attempt to figure out the remote SSL…
CURLOPT_SSLKEYTYPE – set type of the private key file Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLKEYTYPE, char *type); DescriptionPass a pointer to a zero terminated string as parameter. The string should be the format of your private key. Supported formats are "PEM", "DER" and "ENG". The format "ENG" enables you to load the private key from…
CURLOPT_SSLKEY – specify private keyfile for TLS and SSL client cert Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLKEY, char *keyfile); DescriptionPass a pointer to a zero terminated string as parameter. The string should be the file name of your private key. The default format is "PEM" and can be changed with CURLOPT_SSLKEYTYPE(3). (iOS and Mac OS…
CURLOPT_SSLENGINE_DEFAULT – make SSL engine default Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLENGINE_DEFAULT, long val); DescriptionPass a long set to 1 as parameter. Sets the actual crypto engine as the default for (asymmetric) crypto operations. If the crypto device cannot be set, CURLE_SSL_ENGINE_SETFAILED is returned. DefaultNone ProtocolsAll TLS based protocols: HTTPS, FTPS, IMAPS, POP3, SMTPS etc….
CURLOPT_SSLENGINE – set SSL engine identifier Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLENGINE, char *id); DescriptionPass a pointer to a zero terminated string as parameter. It will be used as the identifier for the crypto engine you want to use for your private key. If the crypto device cannot be loaded, CURLE_SSL_ENGINE_NOTFOUND is returned. DefaultNULL ProtocolsAll…
CURLOPT_SSLCERTTYPE – specify type of the client SSL certificate Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERTTYPE, char *type); DescriptionPass a pointer to a zero terminated string as parameter. The string should be the format of your certificate. Supported formats are "PEM" and "DER", except with Secure Transport. OpenSSL (versions 0.9.3 and later) and Secure Transport (on…
CURLOPT_SSLCERT – set SSL client certificate Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERT, char *cert); DescriptionPass a pointer to a zero terminated string as parameter. The string should be the file name of your client certificate. The default format is "P12" on Secure Transport and "PEM" on other engines, and can be changed with CURLOPT_SSLCERTTYPE(3). With…
CURLOPT_SSH_PUBLIC_KEYFILE – set public key file for SSH auth Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_PUBLIC_KEYFILE, char *filename);DescriptionPass a char * pointing to a filename for your public key. If not used, libcurl defaults to $HOME/.ssh/id_dsa.pub if the HOME environment variable is set, and just "id_dsa.pub" in the current directory if HOME is not set. If…
CURLOPT_SSH_PRIVATE_KEYFILE – set private key file for SSH auth Synopsis#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_PRIVATE_KEYFILE, char *filename);DescriptionPass a char * pointing to a filename for your private key. If not used, libcurl defaults to $HOME/.ssh/id_dsa if the HOME environment variable is set, and just "id_dsa" in the current directory if HOME is not set. If…