=pod =head1 NAME SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup, SSL_want_async, SSL_want_async_job, SSL_want_client_hello_cb - obtain state information TLS/SSL I/O operation =head1 SYNOPSIS #include <openssl/ssl.h> int SSL_want(const SSL *ssl); int SSL_want_nothing(const SSL *ssl); int SSL_want_read(const SSL *ssl); int SSL_want_write(const SSL *ssl); int SSL_want_x509_lookup(const SSL *ssl); int SSL_want_async(const SSL *ssl); int SSL_want_async_job(const SSL *ssl); int SSL_want_client_hello_cb(const SSL *ssl); =head1 DESCRIPTION SSL_want() returns state information for the SSL object B<ssl>. The other SSL_want_*() calls are shortcuts for the possible states returned by SSL_want(). =head1 NOTES SSL_want() examines the internal state information of the SSL object. Its return values are similar to that of L<SSL_get_error(3)>. Unlike L<SSL_get_error(3)>, which also evaluates the error queue, the results are obtained by examining an internal state flag only. The information must therefore only be used for normal operation under non-blocking I/O. Error conditions are not handled and must be treated using L<SSL_get_error(3)>. The result returned by SSL_want() should always be consistent with the result of L<SSL_get_error(3)>. =head1 RETURN VALUES The following return values can currently occur for SSL_want(): =over 4 =item SSL_NOTHING There is no data to be written or to be read. =item SSL_WRITING There are data in the SSL buffer that must be written to the underlying B<BIO> layer in order to complete the actual SSL_*() operation. A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_WRITE. =item SSL_READING More data must be read from the underlying B<BIO> layer in order to complete the actual SSL_*() operation. A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_READ. =item SSL_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. A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_X509_LOOKUP. =item SSL_ASYNC_PAUSED An asynchronous operation partially completed and was then paused. See L<SSL_get_all_async_fds(3)>. A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_ASYNC. =item SSL_ASYNC_NO_JOBS The asynchronous job could not be started because there were no async jobs available in the pool (see ASYNC_init_thread(3)). A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_ASYNC_JOB. =item SSL_CLIENT_HELLO_CB The operation did not complete because an application callback set by SSL_CTX_set_client_hello_cb() has asked to be called again. A call to L<SSL_get_error(3)> should return SSL_ERROR_WANT_CLIENT_HELLO_CB. =back SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup(), SSL_want_async(), SSL_want_async_job(), and SSL_want_client_hello_cb() return 1, when the corresponding condition is true or 0 otherwise. =head1 SEE ALSO L<ssl(7)>, L<SSL_get_error(3)> =head1 HISTORY SSL_want_client_hello_cb() and SSL_CLIENT_HELLO_CB were added in OpenSSL 1.1.1. =head1 COPYRIGHT Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L<https://www.openssl.org/source/license.html>. =cut