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<?xml version="1.0" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>SSL_pending</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <link rev="made" href="mailto:root@hsxx.drive.ne.jp" /> </head> <body style="background-color: white"> <!-- INDEX BEGIN --> <div name="index"> <p><a name="__index__"></a></p> <ul> <li><a href="#name">NAME</a></li> <li><a href="#synopsis">SYNOPSIS</a></li> <li><a href="#description">DESCRIPTION</a></li> <li><a href="#return_values">RETURN VALUES</a></li> <li><a href="#see_also">SEE ALSO</a></li> <li><a href="#history">HISTORY</a></li> <li><a href="#copyright">COPYRIGHT</a></li> </ul> <hr name="index" /> </div> <!-- INDEX END --> <p> </p> <hr /> <h1><a name="name">NAME</a></h1> <p>SSL_pending, SSL_has_pending - check for readable bytes buffered in an SSL object</p> <p> </p> <hr /> <h1><a name="synopsis">SYNOPSIS</a></h1> <pre> #include <openssl/ssl.h></pre> <pre> int SSL_pending(const SSL *ssl); int SSL_has_pending(const SSL *s);</pre> <p> </p> <hr /> <h1><a name="description">DESCRIPTION</a></h1> <p>Data is received in whole blocks known as records from the peer. A whole record is processed (e.g. decrypted) in one go and is buffered by OpenSSL until it is read by the application via a call to <em>SSL_read_ex(3)</em> or <em>SSL_read(3)</em>.</p> <p><code>SSL_pending()</code> returns the number of bytes which have been processed, buffered and are available inside <strong>ssl</strong> for immediate read.</p> <p>If the <strong>SSL</strong> object's <em>read_ahead</em> flag is set (see <em>SSL_CTX_set_read_ahead(3)</em>), additional protocol bytes (beyond the current record) may have been read containing more TLS/SSL records. This also applies to DTLS and pipelining (see <em>SSL_CTX_set_split_send_fragment(3)</em>). These additional bytes will be buffered by OpenSSL but will remain unprocessed until they are needed. As these bytes are still in an unprocessed state <code>SSL_pending()</code> will ignore them. Therefore, it is possible for no more bytes to be readable from the underlying BIO (because OpenSSL has already read them) and for <code>SSL_pending()</code> to return 0, even though readable application data bytes are available (because the data is in unprocessed buffered records).</p> <p><code>SSL_has_pending()</code> returns 1 if <strong>s</strong> has buffered data (whether processed or unprocessed) and 0 otherwise. Note that it is possible for <code>SSL_has_pending()</code> to return 1, and then a subsequent call to <code>SSL_read_ex()</code> or <code>SSL_read()</code> to return no data because the unprocessed buffered data when processed yielded no application data (for example this can happen during renegotiation). It is also possible in this scenario for <code>SSL_has_pending()</code> to continue to return 1 even after an <code>SSL_read_ex()</code> or <code>SSL_read()</code> call because the buffered and unprocessed data is not yet processable (e.g. because OpenSSL has only received a partial record so far).</p> <p> </p> <hr /> <h1><a name="return_values">RETURN VALUES</a></h1> <p><code>SSL_pending()</code> returns the number of buffered and processed application data bytes that are pending and are available for immediate read. <code>SSL_has_pending()</code> returns 1 if there is buffered record data in the SSL object and 0 otherwise.</p> <p> </p> <hr /> <h1><a name="see_also">SEE ALSO</a></h1> <p><em>SSL_read_ex(3)</em>, <em>SSL_read(3)</em>, <em>SSL_CTX_set_read_ahead(3)</em>, <em>SSL_CTX_set_split_send_fragment(3)</em>, <em>ssl(7)</em></p> <p> </p> <hr /> <h1><a name="history">HISTORY</a></h1> <p>The <code>SSL_has_pending()</code> function was added in OpenSSL 1.1.0.</p> <p> </p> <hr /> <h1><a name="copyright">COPYRIGHT</a></h1> <p>Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.</p> <p>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 <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p> </body> </html>