More complete X509_check_host documentation.

[openssl.git] / doc / ssl / SSL_read.pod

diff --git a/doc/ssl/SSL_read.pod b/doc/ssl/SSL_read.pod
index 6b47f2fbd1bb95e5834546dc4618bbaacde3f51d..8ca0ce5058da0e5f1299e16d559067e5983737d8 100644 (file)
--- a/doc/ssl/SSL_read.pod
+++ b/doc/ssl/SSL_read.pod
@@ -64,6 +64,11 @@ non-blocking socket, nothing is to be done, but select() can be used to check
 for the required condition. When using a buffering BIO, like a BIO pair, data
 must be written into or retrieved out of the BIO before being able to continue.
 
+L<SSL_pending(3)|SSL_pending(3)> can be used to find out whether there
+are buffered bytes available for immediate retrieval. In this case
+SSL_read() can be called without blocking or actually receiving new
+data from the underlying socket.
+
 =head1 WARNING
 
 When an SSL_read() operation has to be repeated because of
@@ -81,13 +86,15 @@ The following return values can occur:
 The read operation was successful; the return value is the number of
 bytes actually read from the TLS/SSL connection.
 
-=item 0
+=item Z<>0
 
-The read operation was not successful, the SSL connection was closed by the
-peer by sending a "close notify" alert. The SSL_RECEIVED_SHUTDOWN flag in
-the ssl shutdown state is set (see L<SSL_shutdown(3)|SSL_shutdown(3)>,
-L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>).
-Call SSL_get_error() with the return value B<ret> to find out,
+The read operation was not successful. The reason may either be a clean
+shutdown due to a "close notify" alert sent by the peer (in which case
+the SSL_RECEIVED_SHUTDOWN flag in the ssl shutdown state is set
+(see L<SSL_shutdown(3)|SSL_shutdown(3)>,
+L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>). It is also possible, that
+the peer simply shut down the underlying transport and the shutdown is
+incomplete. Call SSL_get_error() with the return value B<ret> to find out,
 whether an error occurred or the connection was shut down cleanly
 (SSL_ERROR_ZERO_RETURN).
 
@@ -110,6 +117,7 @@ L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_write(3)|SSL_write(3)>,
 L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)>, L<SSL_CTX_new(3)|SSL_CTX_new(3)>,
 L<SSL_connect(3)|SSL_connect(3)>, L<SSL_accept(3)|SSL_accept(3)>
 L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>,
+L<SSL_pending(3)|SSL_pending(3)>,
 L<SSL_shutdown(3)|SSL_shutdown(3)>, L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>,
 L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>