1SSL_WANT(3)                         OpenSSL                        SSL_WANT(3)
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NAME

6       SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write,
7       SSL_want_x509_lookup, SSL_want_async, SSL_want_async_job,
8       SSL_want_client_hello_cb - obtain state information TLS/SSL I/O
9       operation
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SYNOPSIS

12        #include <openssl/ssl.h>
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14        int SSL_want(const SSL *ssl);
15        int SSL_want_nothing(const SSL *ssl);
16        int SSL_want_read(const SSL *ssl);
17        int SSL_want_write(const SSL *ssl);
18        int SSL_want_x509_lookup(const SSL *ssl);
19        int SSL_want_async(const SSL *ssl);
20        int SSL_want_async_job(const SSL *ssl);
21        int SSL_want_client_hello_cb(const SSL *ssl);
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DESCRIPTION

24       SSL_want() returns state information for the SSL object ssl.
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26       The other SSL_want_*() calls are shortcuts for the possible states
27       returned by SSL_want().
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NOTES

30       SSL_want() examines the internal state information of the SSL object.
31       Its return values are similar to that of SSL_get_error(3).  Unlike
32       SSL_get_error(3), which also evaluates the error queue, the results are
33       obtained by examining an internal state flag only. The information must
34       therefore only be used for normal operation under non-blocking I/O.
35       Error conditions are not handled and must be treated using
36       SSL_get_error(3).
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38       The result returned by SSL_want() should always be consistent with the
39       result of SSL_get_error(3).
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RETURN VALUES

42       The following return values can currently occur for SSL_want():
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44       SSL_NOTHING
45           There is no data to be written or to be read.
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47       SSL_WRITING
48           There are data in the SSL buffer that must be written to the
49           underlying BIO layer in order to complete the actual SSL_*()
50           operation.  A call to SSL_get_error(3) should return
51           SSL_ERROR_WANT_WRITE.
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53       SSL_READING
54           More data must be read from the underlying BIO layer in order to
55           complete the actual SSL_*() operation.  A call to SSL_get_error(3)
56           should return SSL_ERROR_WANT_READ.
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58       SSL_X509_LOOKUP
59           The operation did not complete because an application callback set
60           by SSL_CTX_set_client_cert_cb() has asked to be called again.  A
61           call to SSL_get_error(3) should return SSL_ERROR_WANT_X509_LOOKUP.
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63       SSL_ASYNC_PAUSED
64           An asynchronous operation partially completed and was then paused.
65           See SSL_get_all_async_fds(3). A call to SSL_get_error(3) should
66           return SSL_ERROR_WANT_ASYNC.
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68       SSL_ASYNC_NO_JOBS
69           The asynchronous job could not be started because there were no
70           async jobs available in the pool (see ASYNC_init_thread(3)). A call
71           to SSL_get_error(3) should return SSL_ERROR_WANT_ASYNC_JOB.
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73       SSL_CLIENT_HELLO_CB
74           The operation did not complete because an application callback set
75           by SSL_CTX_set_client_hello_cb() has asked to be called again.  A
76           call to SSL_get_error(3) should return
77           SSL_ERROR_WANT_CLIENT_HELLO_CB.
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79       SSL_want_nothing(), SSL_want_read(), SSL_want_write(),
80       SSL_want_x509_lookup(), SSL_want_async(), SSL_want_async_job(), and
81       SSL_want_client_hello_cb() return 1, when the corresponding condition
82       is true or 0 otherwise.
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SEE ALSO

85       ssl(7), SSL_get_error(3)
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HISTORY

88       SSL_want_client_hello_cb() and SSL_CLIENT_HELLO_CB were added in
89       OpenSSL 1.1.1.
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92       Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.
93
94       Licensed under the OpenSSL license (the "License").  You may not use
95       this file except in compliance with the License.  You can obtain a copy
96       in the file LICENSE in the source distribution or at
97       <https://www.openssl.org/source/license.html>.
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1011.1.1                             2018-09-11                       SSL_WANT(3)
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