int SSL_get_read_ahead(const SSL *s);
void SSL_set_read_ahead(SSL *s, int yes);
DESCRIPTIONSSL_CTX_set_read_ahead() and SSL_set_read_ahead() set whether we should read as many input bytes as possible (for non-blocking reads) or not. For example if x bytes are currently required by OpenSSL, but y bytes are available from the underlying BIO (where y > x), then OpenSSL will read all y bytes into its buffer (providing that the buffer is large enough) if reading ahead is on, or x bytes otherwise. The parameter yes or m should be 0 to ensure reading ahead is off, or non zero otherwise.
SSL_CTX_set_default_read_ahead is a synonym for SSL_CTX_set_read_ahead, and SSL_CTX_get_default_read_ahead is a synonym for SSL_CTX_get_read_ahead.
SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading ahead has been set or not.