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SSL_get_error(3)                                   OpenSSL                                  SSL_get_error(3)



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

SYNOPSIS
        #include <openssl/ssl.h>

        int SSL_get_error(const SSL *ssl, int ret);

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(), SSL_peek(), or SSL_write() on ssl.  The
       value returned by that TLS/SSL I/O function must be passed to SSL_get_error() in parameter ret.

       In addition to ssl and 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.

RETURN VALUES
       The following return values can currently occur:

       SSL_ERROR_NONE
           The TLS/SSL I/O operation completed.  This result code is returned if and only if ret > 0.

       SSL_ERROR_ZERO_RETURN
           The TLS/SSL connection has been closed.  If the protocol version is SSL 3.0 or TLS 1.0, 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 SSL_ERROR_ZERO_RETURN does not
           necessarily indicate that the underlying transport has been closed.

       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 BIO has data available for reading (if the result code is
           SSL_ERROR_WANT_READ) or allows writing data (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 SSL_ERROR_WANT_READ or 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 BIOs (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 SSL_ERROR_WANT_READ and
           SSL_ERROR_WANT_WRITE.  In particular, SSL_read() or SSL_peek() may want to write data and
           SSL_write() 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(), SSL_peek(),
           and SSL_write() will handle any pending handshakes.

       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.

       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.

       SSL_ERROR_SYSCALL
           Some I/O error occurred.  The OpenSSL error queue may contain more information on the error.  If
           the error queue is empty (i.e. ERR_get_error() returns 0), ret can be used to find out more about
           the error: If ret == 0, an EOF was observed that violates the protocol.  If ret == -1, the
           underlying BIO reported an I/O error (for socket I/O on Unix systems, consult errno for details).

       SSL_ERROR_SSL
           A failure in the SSL library occurred, usually a protocol error.  The OpenSSL error queue
           contains more information on the error.

SEE ALSO
       ssl(3), err(3)

HISTORY
       SSL_get_error() was added in SSLeay 0.8.



50                                               2013-03-05                                 SSL_get_error(3)