ciphers supported by both client and
*ssl, char *buf, int
puts the names of the ciphers that are supported by both the client and the
server of ssl into the buffer
buf. Names are separated by colons. At most
len bytes are written to buf
including the terminating NUL character.
If ssl contains no session, if the session
contains no shared ciphers, or if len is less than 2,
NULL. Otherwise, it returns
SSL_get_shared_ciphers() first appeared in
SSLeay 0.4.5b and has been available since OpenBSD
If the list is too long to fit into len bytes, it is silently truncated after the last cipher name that fits, and all following ciphers are skipped. If the buffer is very short such that even the first cipher name does not fit, an empty string is returned even when some shared ciphers are actually available.
There is no easy way to find out how much space is required for buf or whether the supplied space was sufficient.