OpenSSL 1.1.1-pre2

doc/man3/SSL_get_error.pod

@@ -0,0 +1,151 @@
+=pod
+
+=head1 NAME
+
+SSL_get_error - obtain result code for TLS/SSL I/O operation
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ int SSL_get_error(const SSL *ssl, int ret);
+
+=head1 DESCRIPTION
+
+SSL_get_error() returns a result code (suitable for the C "switch"
+statement) for a preceding call to SSL_connect(), SSL_accept(), SSL_do_handshake(),
+SSL_read_ex(), SSL_read(), SSL_peek_ex(), SSL_peek(), SSL_write_ex() or
+SSL_write() on B<ssl>.  The value returned by that TLS/SSL I/O function must be
+passed to SSL_get_error() in parameter B<ret>.
+
+In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
+current thread's OpenSSL error queue.  Thus, SSL_get_error() must be
+used in the same thread that performed the TLS/SSL I/O operation, and no
+other OpenSSL function calls should appear in between.  The current
+thread's error queue must be empty before the TLS/SSL I/O operation is
+attempted, or SSL_get_error() will not work reliably.
+
+=head1 RETURN VALUES
+
+The following return values can currently occur:
+
+=over 4
+
+=item SSL_ERROR_NONE
+
+The TLS/SSL I/O operation completed.  This result code is returned
+if and only if B<ret E<gt> 0>.
+
+=item SSL_ERROR_ZERO_RETURN
+
+The TLS/SSL connection has been closed.
+If the protocol version is SSL 3.0 or higher, this result code is returned only
+if a closure alert has occurred in the protocol, i.e. if the connection has been
+closed cleanly.
+Note that in this case B<SSL_ERROR_ZERO_RETURN> does not necessarily
+indicate that the underlying transport has been closed.
+
+=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
+
+The operation did not complete; the same TLS/SSL I/O function should be
+called again later.  If, by then, the underlying B<BIO> has data
+available for reading (if the result code is B<SSL_ERROR_WANT_READ>)
+or allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL
+protocol progress will take place, i.e. at least part of an TLS/SSL
+record will be read or written.  Note that the retry may again lead to
+a B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition.
+There is no fixed upper limit for the number of iterations that
+may be necessary until progress becomes visible at application
+protocol level.
+
+For socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or
+poll() on the underlying socket can be used to find out when the
+TLS/SSL I/O function should be retried.
+
+Caveat: Any TLS/SSL I/O function can lead to either of
+B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>.  In particular,
+SSL_read_ex(), SSL_read(), SSL_peek_ex(), or SSL_peek() may want to write data
+and SSL_write() or SSL_write_ex() may want to read data.  This is mainly because
+TLS/SSL handshakes may occur at any time during the protocol (initiated by
+either the client or the server); SSL_read_ex(), SSL_read(), SSL_peek_ex(),
+SSL_peek(), SSL_write_ex(), and SSL_write() will handle any pending handshakes.
+
+=item SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT
+
+The operation did not complete; the same TLS/SSL I/O function should be
+called again later. The underlying BIO was not connected yet to the peer
+and the call would block in connect()/accept(). The SSL function should be
+called again when the connection is established. These messages can only
+appear with a BIO_s_connect() or BIO_s_accept() BIO, respectively.
+In order to find out, when the connection has been successfully established,
+on many platforms select() or poll() for writing on the socket file descriptor
+can be used.
+
+=item SSL_ERROR_WANT_X509_LOOKUP
+
+The operation did not complete because an application callback set by
+SSL_CTX_set_client_cert_cb() has asked to be called again.
+The TLS/SSL I/O function should be called again later.
+Details depend on the application.
+
+=item SSL_ERROR_WANT_ASYNC
+
+The operation did not complete because an asynchronous engine is still
+processing data. This will only occur if the mode has been set to SSL_MODE_ASYNC
+using L<SSL_CTX_set_mode(3)> or L<SSL_set_mode(3)> and an asynchronous capable
+engine is being used. An application can determine whether the engine has
+completed its processing using select() or poll() on the asynchronous wait file
+descriptor. This file descriptor is available by calling
+L<SSL_get_all_async_fds(3)> or L<SSL_get_changed_async_fds(3)>. The TLS/SSL I/O
+function should be called again later. The function B<must> be called from the
+same thread that the original call was made from.
+
+=item SSL_ERROR_WANT_ASYNC_JOB
+
+The asynchronous job could not be started because there were no async jobs
+available in the pool (see ASYNC_init_thread(3)). This will only occur if the
+mode has been set to SSL_MODE_ASYNC using L<SSL_CTX_set_mode(3)> or
+L<SSL_set_mode(3)> and a maximum limit has been set on the async job pool
+through a call to L<ASYNC_init_thread(3)>. The application should retry the
+operation after a currently executing asynchronous operation for the current
+thread has completed.
+
+=item SSL_ERROR_WANT_CLIENT_HELLO_CB
+
+The operation did not complete because an application callback set by
+SSL_CTX_set_client_hello_cb() has asked to be called again.
+The TLS/SSL I/O function should be called again later.
+Details depend on the application.
+
+=item SSL_ERROR_SYSCALL
+
+Some non-recoverable I/O error occurred.
+The OpenSSL error queue may contain more information on the error.
+For socket I/O on Unix systems, consult B<errno> for details.
+
+=item SSL_ERROR_SSL
+
+A failure in the SSL library occurred, usually a protocol error.  The
+OpenSSL error queue contains more information on the error.
+
+=back
+
+=head1 SEE ALSO
+
+L<ssl(7)>
+
+=head1 HISTORY
+
+SSL_ERROR_WANT_ASYNC was added in OpenSSL 1.1.0.
+SSL_ERROR_WANT_CLIENT_HELLO_CB was added in OpenSSL 1.1.1.
+
+=head1 COPYRIGHT
+
+Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut