NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

        #include <openssl/ssl.h>

        int SSL_get_error(SSL *ssl, int ret);

DESCRIPTION    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       ssl(3), err(3)

HISTORY    [Toc]    [Back]

       SSL_get_error() was added in SSLeay 0.8.


OpenBSD 3.6                 2002-09-10                          3