SSL_get_error.pod revision 68651
1=pod 2 3=head1 NAME 4 5SSL_get_error - obtain result code for TLS/SSL I/O operation 6 7=head1 SYNOPSIS 8 9 #include <openssl/ssl.h> 10 11 int SSL_get_error(SSL *ssl, int ret); 12 13=head1 DESCRIPTION 14 15SSL_get_error() returns a result code (suitable for the C "switch" 16statement) for a preceding call to SSL_connect(), SSL_accept(), 17SSL_read(), or SSL_write() on B<ssl>. The value returned by that 18TLS/SSL I/O function must be passed to SSL_get_error() in parameter 19B<ret>. 20 21In addition to B<ssl> and B<ret>, SSL_get_error() inspects the 22current thread's OpenSSL error queue. Thus, SSL_get_error() must be 23used in the same thread that performed the TLS/SSL I/O operation, and no 24other OpenSSL function calls should appear in between. The current 25thread's error queue must be empty before the TLS/SSL I/O operation is 26attempted, or SSL_get_error() will not work reliably. 27 28=head1 RETURN VALUES 29 30The following return values can currently occur: 31 32=over 4 33 34=item SSL_ERROR_NONE 35 36The TLS/SSL I/O operation completed. This result code is returned 37if and only if B<ret E<gt> 0>. 38 39=item SSL_ERROR_ZERO_RETURN 40 41The TLS/SSL connection has been closed. If the protocol version is SSL 3.0 42or TLS 1.0, this result code is returned only if a closure 43alert has occurred in the protocol, i.e. if the connection has been 44closed cleanly. Note that in this case B<SSL_ERROR_ZERO_RETURN> 45does not necessarily indicate that the underlying transport 46has been closed. 47 48=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE 49 50The operation did not complete; the same TLS/SSL I/O function should be 51called again later. There will be protocol progress if, by then, the 52underlying B<BIO> has data available for reading (if the result code is 53B<SSL_ERROR_WANT_READ>) or allows writing data (B<SSL_ERROR_WANT_WRITE>). 54For socket B<BIO>s (e.g. when SSL_set_fd() was used) this means that 55select() or poll() on the underlying socket can be used to find out 56when the TLS/SSL I/O function should be retried. 57 58Caveat: Any TLS/SSL I/O function can lead to either of 59B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>, i.e. SSL_read() 60may want to write data and SSL_write() may want to read data. 61 62=item SSL_ERROR_WANT_X509_LOOKUP 63 64The operation did not complete because an application callback set by 65SSL_CTX_set_client_cert_cb() has asked to be called again. 66The TLS/SSL I/O function should be called again later. 67Details depend on the application. 68 69=item SSL_ERROR_SYSCALL 70 71Some I/O error occurred. The OpenSSL error queue may contain more 72information on the error. If the error queue is empty 73(i.e. ERR_get_error() returns 0), B<ret> can be used to find out more 74about the error: If B<ret == 0>, an EOF was observed that violates 75the protocol. If B<ret == -1>, the underlying B<BIO> reported an 76I/O error (for socket I/O on Unix systems, consult B<errno> for details). 77 78=item SSL_ERROR_SSL 79 80A failure in the SSL library occurred, usually a protocol error. The 81OpenSSL error queue contains more information on the error. 82 83=back 84 85=head1 SEE ALSO 86 87L<ssl(3)|ssl(3)>, L<err(3)|err(3)> 88 89=head1 HISTORY 90 91SSL_get_error() was added in SSLeay 0.8. 92 93=cut 94