SSL_get_error(3)            OpenSSL            SSL_get_error(3)





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

SYNOPSIS
        #include <openssl/ssl.h>

        int SSL_get_error(SSL *ssl, int ret);

DESCRIPTION
       SSL_get_error() returns a result code (suitable for the
       C "switch" statement) for a preceding call to SSL_con-
       nect(), 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 pro-
           tocol 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 condi-
           tion.  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 underly-
           ing 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, respec-
           tively.  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 applica-
           tion callback set by SSL_CTX_set_client_cert_cb()
           has asked to be called again.  The TLS/SSL I/O func-
           tion 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 vio-
           lates 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.



0.9.7c                     2002-07-29          SSL_get_error(3)
