1SSL_get_error(3)                    OpenSSL                   SSL_get_error(3)
2
3
4

NAME

6       SSL_get_error - obtain result code for TLS/SSL I/O operation
7

SYNOPSIS

9        #include <openssl/ssl.h>
10
11        int SSL_get_error(const SSL *ssl, int ret);
12

DESCRIPTION

14       SSL_get_error() returns a result code (suitable for the C "switch"
15       statement) for a preceding call to SSL_connect(), SSL_accept(),
16       SSL_do_handshake(), SSL_read(), SSL_peek(), or SSL_write() on ssl.  The
17       value returned by that TLS/SSL I/O function must be passed to
18       SSL_get_error() in parameter ret.
19
20       In addition to ssl and ret, SSL_get_error() inspects the current
21       thread's OpenSSL error queue.  Thus, SSL_get_error() must be used in
22       the same thread that performed the TLS/SSL I/O operation, and no other
23       OpenSSL function calls should appear in between.  The current thread's
24       error queue must be empty before the TLS/SSL I/O operation is
25       attempted, or SSL_get_error() will not work reliably.
26

RETURN VALUES

28       The following return values can currently occur:
29
30       SSL_ERROR_NONE
31           The TLS/SSL I/O operation completed.  This result code is returned
32           if and only if ret > 0.
33
34       SSL_ERROR_ZERO_RETURN
35           The TLS/SSL connection has been closed.  If the protocol version is
36           SSL 3.0 or higher, this result code is returned only if a closure
37           alert has occurred in the protocol, i.e. if the connection has been
38           closed cleanly.  Note that in this case SSL_ERROR_ZERO_RETURN does
39           not necessarily indicate that the underlying transport has been
40           closed.
41
42       SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
43           The operation did not complete; the same TLS/SSL I/O function
44           should be called again later.  If, by then, the underlying BIO has
45           data available for reading (if the result code is
46           SSL_ERROR_WANT_READ) or allows writing data (SSL_ERROR_WANT_WRITE),
47           then some TLS/SSL protocol progress will take place, i.e. at least
48           part of an TLS/SSL record will be read or written.  Note that the
49           retry may again lead to a SSL_ERROR_WANT_READ or
50           SSL_ERROR_WANT_WRITE condition.  There is no fixed upper limit for
51           the number of iterations that may be necessary until progress
52           becomes visible at application protocol level.
53
54           For socket BIOs (e.g. when SSL_set_fd() was used), select() or
55           poll() on the underlying socket can be used to find out when the
56           TLS/SSL I/O function should be retried.
57
58           Caveat: Any TLS/SSL I/O function can lead to either of
59           SSL_ERROR_WANT_READ and SSL_ERROR_WANT_WRITE.  In particular,
60           SSL_read() or SSL_peek() may want to write data and SSL_write() may
61           want to read data.  This is mainly because TLS/SSL handshakes may
62           occur at any time during the protocol (initiated by either the
63           client or the server); SSL_read(), SSL_peek(), and SSL_write() will
64           handle any pending handshakes.
65
66       SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT
67           The operation did not complete; the same TLS/SSL I/O function
68           should be called again later. The underlying BIO was not connected
69           yet to the peer and the call would block in connect()/accept(). The
70           SSL function should be called again when the connection is
71           established. These messages can only appear with a BIO_s_connect()
72           or BIO_s_accept() BIO, respectively.  In order to find out, when
73           the connection has been successfully established, on many platforms
74           select() or poll() for writing on the socket file descriptor can be
75           used.
76
77       SSL_ERROR_WANT_X509_LOOKUP
78           The operation did not complete because an application callback set
79           by SSL_CTX_set_client_cert_cb() has asked to be called again.  The
80           TLS/SSL I/O function should be called again later.  Details depend
81           on the application.
82
83       SSL_ERROR_SYSCALL
84           Some non-recoverable I/O error occurred.  The OpenSSL error queue
85           may contain more information on the error.  For socket I/O on Unix
86           systems, consult errno for details.
87
88       SSL_ERROR_SSL
89           A failure in the SSL library occurred, usually a protocol error.
90           The OpenSSL error queue contains more information on the error.
91

SEE ALSO

93       ssl(3), err(3)
94

HISTORY

96       SSL_get_error() was added in SSLeay 0.8.
97
98
99
1001.0.2o                            2020-08-01                  SSL_get_error(3)
Impressum