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✏️ Editing: SSL_want_write.3

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.\" ========================================================================
.\"
.IX Title "SSL_WANT 3"
.TH SSL_WANT 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "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
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #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);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBSSL_want()\fR returns state information for the \s-1SSL\s0 object \fBssl\fR.
.PP
The other SSL_want_*() calls are shortcuts for the possible states returned
by \fBSSL_want()\fR.
.SH "NOTES"
.IX Header "NOTES"
\&\fBSSL_want()\fR examines the internal state information of the \s-1SSL\s0 object. Its
return values are similar to that of \fBSSL_get_error\fR\|(3).
Unlike \fBSSL_get_error\fR\|(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
nonblocking I/O. Error conditions are not handled and must be treated
using \fBSSL_get_error\fR\|(3).
.PP
The result returned by \fBSSL_want()\fR should always be consistent with
the result of \fBSSL_get_error\fR\|(3).
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
The following return values can currently occur for \fBSSL_want()\fR:
.IP "\s-1SSL_NOTHING\s0" 4
.IX Item "SSL_NOTHING"
There is no data to be written or to be read.
.IP "\s-1SSL_WRITING\s0" 4
.IX Item "SSL_WRITING"
There are data in the \s-1SSL\s0 buffer that must be written to the underlying
\&\fB\s-1BIO\s0\fR layer in order to complete the actual SSL_*() operation.
A call to \fBSSL_get_error\fR\|(3) should return
\&\s-1SSL_ERROR_WANT_WRITE.\s0
.IP "\s-1SSL_READING\s0" 4
.IX Item "SSL_READING"
More data must be read from the underlying \fB\s-1BIO\s0\fR layer in order to
complete the actual SSL_*() operation.
A call to \fBSSL_get_error\fR\|(3) should return
\&\s-1SSL_ERROR_WANT_READ.\s0
.IP "\s-1SSL_X509_LOOKUP\s0" 4
.IX Item "SSL_X509_LOOKUP"
The operation did not complete because an application callback set by
\&\fBSSL_CTX_set_client_cert_cb()\fR has asked to be called again.
A call to \fBSSL_get_error\fR\|(3) should return
\&\s-1SSL_ERROR_WANT_X509_LOOKUP.\s0
.IP "\s-1SSL_ASYNC_PAUSED\s0" 4
.IX Item "SSL_ASYNC_PAUSED"
An asynchronous operation partially completed and was then paused. See
\&\fBSSL_get_all_async_fds\fR\|(3). A call to \fBSSL_get_error\fR\|(3) should return
\&\s-1SSL_ERROR_WANT_ASYNC.\s0
.IP "\s-1SSL_ASYNC_NO_JOBS\s0" 4
.IX Item "SSL_ASYNC_NO_JOBS"
The asynchronous job could not be started because there were no async jobs
available in the pool (see \fBASYNC_init_thread\fR\|(3)). A call to \fBSSL_get_error\fR\|(3)
should return \s-1SSL_ERROR_WANT_ASYNC_JOB.\s0
.IP "\s-1SSL_CLIENT_HELLO_CB\s0" 4
.IX Item "SSL_CLIENT_HELLO_CB"
The operation did not complete because an application callback set by
\&\fBSSL_CTX_set_client_hello_cb()\fR has asked to be called again.
A call to \fBSSL_get_error\fR\|(3) should return
\&\s-1SSL_ERROR_WANT_CLIENT_HELLO_CB.\s0
.PP
\&\fBSSL_want_nothing()\fR, \fBSSL_want_read()\fR, \fBSSL_want_write()\fR, \fBSSL_want_x509_lookup()\fR,
\&\fBSSL_want_async()\fR, \fBSSL_want_async_job()\fR, and \fBSSL_want_client_hello_cb()\fR return
1, when the corresponding condition is true or 0 otherwise.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBssl\fR\|(7), \fBSSL_get_error\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
The \fBSSL_want_client_hello_cb()\fR function and the \s-1SSL_CLIENT_HELLO_CB\s0 return value
were added in OpenSSL 1.1.1.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2001\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB