OpenSSL

Cryptography and SSL/TLS Toolkit

SSL_want

NAME

SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup, SSL_want_async, SSL_want_async_job - obtain state information TLS/SSL I/O operation

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);

DESCRIPTION

SSL_want() returns state information for the SSL object ssl.

The other SSL_want_*() calls are shortcuts for the possible states returned by SSL_want().

NOTES

SSL_want() examines the internal state information of the SSL object. Its return values are similar to that of SSL_get_error. Unlike SSL_get_error, 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 SSL_get_error.

The result returned by SSL_want() should always be consistent with the result of SSL_get_error.

RETURN VALUES

The following return values can currently occur for SSL_want():

SSL_NOTHING

There is no data to be written or to be read.

SSL_WRITING

There are data in the SSL buffer that must be written to the underlying BIO layer in order to complete the actual SSL_*() operation. A call to SSL_get_error should return SSL_ERROR_WANT_WRITE.

SSL_READING

More data must be read from the underlying BIO layer in order to complete the actual SSL_*() operation. A call to SSL_get_error should return SSL_ERROR_WANT_READ.

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 SSL_get_error should return SSL_ERROR_WANT_X509_LOOKUP.

SSL_ASYNC_PAUSED

An asynchronous operation partially completed and was then paused. See SSL_get_all_async_fds. A call to SSL_get_error should return SSL_ERROR_WANT_ASYNC.

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 SSL_get_error should return SSL_ERROR_WANT_ASYNC_JOB.

SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup(), SSL_want_async() and SSL_want_async_job() return 1, when the corresponding condition is true or 0 otherwise.

SEE ALSO

ssl, err, SSL_get_error

Copyright 2001-2016 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 https://www.openssl.org/source/license.html.