1=pod 2 3=head1 NAME 4 5SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup, 6SSL_want_async, SSL_want_async_job, SSL_want_client_hello_cb - obtain state 7information TLS/SSL I/O operation 8 9=head1 SYNOPSIS 10 11 #include <openssl/ssl.h> 12 13 int SSL_want(const SSL *ssl); 14 int SSL_want_nothing(const SSL *ssl); 15 int SSL_want_read(const SSL *ssl); 16 int SSL_want_write(const SSL *ssl); 17 int SSL_want_x509_lookup(const SSL *ssl); 18 int SSL_want_async(const SSL *ssl); 19 int SSL_want_async_job(const SSL *ssl); 20 int SSL_want_client_hello_cb(const SSL *ssl); 21 22=head1 DESCRIPTION 23 24SSL_want() returns state information for the SSL object B<ssl>. 25 26The other SSL_want_*() calls are shortcuts for the possible states returned 27by SSL_want(). 28 29=head1 NOTES 30 31SSL_want() examines the internal state information of the SSL object. Its 32return values are similar to that of L<SSL_get_error(3)>. 33Unlike L<SSL_get_error(3)>, which also evaluates the 34error queue, the results are obtained by examining an internal state flag 35only. The information must therefore only be used for normal operation under 36nonblocking I/O. Error conditions are not handled and must be treated 37using L<SSL_get_error(3)>. 38 39The result returned by SSL_want() should always be consistent with 40the result of L<SSL_get_error(3)>. 41 42=head1 RETURN VALUES 43 44The following return values can currently occur for SSL_want(): 45 46=over 4 47 48=item SSL_NOTHING 49 50There is no data to be written or to be read. 51 52=item SSL_WRITING 53 54There are data in the SSL buffer that must be written to the underlying 55B<BIO> layer in order to complete the actual SSL_*() operation. 56A call to L<SSL_get_error(3)> should return 57SSL_ERROR_WANT_WRITE. 58 59=item SSL_READING 60 61More data must be read from the underlying B<BIO> layer in order to 62complete the actual SSL_*() operation. 63A call to L<SSL_get_error(3)> should return 64SSL_ERROR_WANT_READ. 65 66=item SSL_X509_LOOKUP 67 68The operation did not complete because an application callback set by 69SSL_CTX_set_client_cert_cb() has asked to be called again. 70A call to L<SSL_get_error(3)> should return 71SSL_ERROR_WANT_X509_LOOKUP. 72 73=item SSL_ASYNC_PAUSED 74 75An asynchronous operation partially completed and was then paused. See 76L<SSL_get_all_async_fds(3)>. A call to L<SSL_get_error(3)> should return 77SSL_ERROR_WANT_ASYNC. 78 79=item SSL_ASYNC_NO_JOBS 80 81The asynchronous job could not be started because there were no async jobs 82available in the pool (see ASYNC_init_thread(3)). A call to L<SSL_get_error(3)> 83should return SSL_ERROR_WANT_ASYNC_JOB. 84 85=item SSL_CLIENT_HELLO_CB 86 87The operation did not complete because an application callback set by 88SSL_CTX_set_client_hello_cb() has asked to be called again. 89A call to L<SSL_get_error(3)> should return 90SSL_ERROR_WANT_CLIENT_HELLO_CB. 91 92=back 93 94SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup(), 95SSL_want_async(), SSL_want_async_job(), and SSL_want_client_hello_cb() return 961, when the corresponding condition is true or 0 otherwise. 97 98=head1 SEE ALSO 99 100L<ssl(7)>, L<SSL_get_error(3)> 101 102=head1 HISTORY 103 104The SSL_want_client_hello_cb() function and the SSL_CLIENT_HELLO_CB return value 105were added in OpenSSL 1.1.1. 106 107=head1 COPYRIGHT 108 109Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved. 110 111Licensed under the OpenSSL license (the "License"). You may not use 112this file except in compliance with the License. You can obtain a copy 113in the file LICENSE in the source distribution or at 114L<https://www.openssl.org/source/license.html>. 115 116=cut 117