1SSL_get_error(3)                    OpenSSL                   SSL_get_error(3)
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NAME

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

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

28       The following return values can currently occur:
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30       SSL_ERROR_NONE
31           The TLS/SSL I/O operation completed.  This result code is returned
32           if and only if ret > 0.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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SEE ALSO

93       ssl(3), err(3)
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HISTORY

96       SSL_get_error() was added in SSLeay 0.8.
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1001.0.2o                            2020-01-28                  SSL_get_error(3)
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