New manual page.

doc/ssl/SSL_get_error.pod

+=pod
+
+=head1 NAME
+
+SSL_get_error - obtain result code for SSL I/O operation
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ int SSL_get_error(SSL *ssl, int ret);
+
+=head1 DESCRIPTION
+
+SSL_get_error() returns a result code (suitable for the C "switch"
+statement) for a preceding call to SSL_connect(), SSL_accept(),
+SSL_read(), or SSL_write() on B<ssl>.  The value returned by that
+SSL I/O function must be passed to SSL_get_error() in parameter
+B<ret>.
+
+In addition to B<ssl> and B<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 SSL I/O operation, and no
+other OpenSSL function calls should appear inbetween.  The current
+thread's error queue must be empty before the SSL I/O operation is
+attempted, or SSL_get_error() will not work reliably.
+
+=head1 RETURN VALUES
+
+The following return values can currently occur:
+
+=over 4
+
+=item SSL_ERROR_NONE
+
+The SSL I/O operation completed.  This result code is returned
+if and only if B<ret > 0>.
+
+=item SSL_ERROR_ZERO_RETURN
+
+The 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
+alerts has occured in the protocol, i.e. if the connection has been
+closed cleanly.
+
+=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
+
+The operation did not complete; the same SSL I/O function should be
+called again later.  There will be protocol progress if, by then, the
+underlying B<BIO> has data available for reading (if the result code is
+B<SSL_ERROR_WANT_READ>) or allows writing data (B<SSL_ERROR_WANT_WRITE>). 
+For socket B<BIO>s (e.g. when SSL_set_fd() was used) this means that
+select() or poll() on the underlying socket can be used to find out
+when the SSL I/O function should be retried.
+
+Caveat: Any SSL I/O function can lead to either of
+B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>, i.e. SSL_read()
+may want to write data and SSL_write() may want to read data.
+
+=item 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 SSL I/O function should be called again later.
+Details depend on the application.
+
+=item 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), B<ret> can be used to find out more
+about the error: If B<ret == 0>, an EOF was observed that violates
+the protocol.  If B<ret == -1>, the underlying B<BIO> reported an
+I/O error.  (For socket I/O on Unix systems, consult B<errno>.)
+
+=item SSL_ERROR_SSL
+
+A failure in the SSL library occured, usually a protocol error.  The
+OpenSSL error queue contains more information on the error.
+
+=back
+
+=head1 SEE ALSO
+
+ssl(3), err(3)
+
+=head1 HISTORY
+
+SSL_get_error() was added in SSLeay 0.8.
+
+=cut