Report version of
libcurl in use.
A character string, with value the
libcurl version in use or
"" if none is. If
libcurl is available, has attributes
A character string naming the SSL implementation
and version, possibly
"none". It is intended for the version
of OpenSSL used, but not all implementations of
OpenSSL --- for example macOS reports
wrapper for SSL/TLS.
A character string naming the
which may or may not be available (it is used for
sftp protocols). Where present,
A character vector of the names of supported protocols, also known as ‘schemes’ when part of a URL.
extSoftVersion for versions of other third-party
http://curl.haxx.se/docs/ssl-compared.html for more details on
SSL versions. Normally
libcurl used with R uses
SecureTransport on macOS, OpenSSL on Windows and GnuTLS, NSS or OpenSSL
on Unix-alikes. (At the time of writing Debian-based Linuxen use
GnuTLS, RedHat-based ones use NSS.)