.\" generated by cd2nroff 0.1 from CURLOPT_USE_SSL.md .TH CURLOPT_USE_SSL 3 "March 22 2024" libcurl .SH NAME CURLOPT_USE_SSL \- request using SSL / TLS for the transfer .SH SYNOPSIS .nf #include CURLcode curl_easy_setopt(CURL *handle, CURLOPT_USE_SSL, long level); .fi .SH DESCRIPTION Pass a long using one of the values from below, to make libcurl use your desired \fIlevel\fP of SSL for the transfer. These are all protocols that start out plain text and get "upgraded" to SSL using the STARTTLS command. This is for enabling SSL/TLS when you use FTP, SMTP, POP3, IMAP etc. .IP CURLUSESSL_NONE do not attempt to use SSL. .IP CURLUSESSL_TRY Try using SSL, proceed as normal otherwise. Note that server may close the connection if the negotiation does not succeed. .IP CURLUSESSL_CONTROL Require SSL for the control connection or fail with \fICURLE_USE_SSL_FAILED\fP. .IP CURLUSESSL_ALL Require SSL for all communication or fail with \fICURLE_USE_SSL_FAILED\fP. .SH DEFAULT CURLUSESSL_NONE .SH PROTOCOLS FTP, SMTP, POP3, IMAP, LDAP .SH EXAMPLE .nf int main(void) { CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/dir/file.ext"); /* require use of SSL for this, or fail */ curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL); /* Perform the request */ curl_easy_perform(curl); } } .fi .SH AVAILABILITY Added in 7.11.0. This option was known as CURLOPT_FTP_SSL up to 7.16.4, and the constants were known as CURLFTPSSL_* Handled by LDAP since 7.81.0. Fully supported by the OpenLDAP backend only. .SH RETURN VALUE Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. .SH SEE ALSO .BR CURLOPT_PROXY_SSLVERSION (3), .BR CURLOPT_SSLVERSION (3), .BR CURLOPT_SSL_OPTIONS (3)