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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(
	  SSL *ssl,
	  int ret );

DESCRIPTION
  The SSL_get_error() function returns a result code (suitable for the C
  switch statement) for a preceding call to the SSL_connect(), SSL_accept(),
  SSL_do_handshake(), SSL_read(), SSL_peek(), or SSL_write() functions on
  ssl.	The value returned by that TLS/SSL I/O function must be passed to the
  SSL_get_error() function in parameter ret.

  In addition to ssl and ret, the SSL_get_error() function inspects the
  current thread's OpenSSL error queue.	 Thus, the SSL_get_error() function
  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 the SSL_get_error() function 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. 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.  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 the SSL_set_fd() function was used), the
	  select() or poll() functions on the underlying socket can be used
	  to determine when the TLS/SSL I/O function should be retried.

	  Caveat: Any TLS/SSL I/O function can lead to either
	  SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE.	In particular, the
	  SSL_read() or SSL_peek() functions might write data, and the
	  SSL_write() function might read data.	 This is because TLS/SSL
	  handshakes can occur at any time during the protocol (initiated by
	  either the client or the server); the SSL_read(), SSL_peek(), and
	  SSL_write() functions 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 the
	  select() or poll() functions 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 theSSL_CTX_set_client_cert_cb() function 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. the
	  ERR_get_error() functions returns 0), ret can be used to learn 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.

HISTORY
  The SSL_get_error() function was added in SSLeay 0.8.

SEE ALSO
  Functions: ssl(3), err(3)

Index for Section 3

Alphabetical listing for S

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