=pod =head1 NAME SSL_pending, SSL_has_pending - check for readable bytes buffered in an SSL object =head1 SYNOPSIS #include int SSL_pending(const SSL *ssl); int SSL_has_pending(const SSL *s); =head1 DESCRIPTION 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 L or L. SSL_pending() returns the number of bytes which have been processed, buffered and are available inside B for immediate read. If the B object's I flag is set (see L), additional protocol bytes (beyond the current record) may have been read containing more TLS/SSL records. This also applies to DTLS and pipelining (see L). 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 SSL_pending() 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 SSL_pending() to return 0, even though readable application data bytes are available (because the data is in unprocessed buffered records). SSL_has_pending() returns 1 if B has buffered data (whether processed or unprocessed) and 0 otherwise. Note that it is possible for SSL_has_pending() to return 1, and then a subsequent call to SSL_read_ex() or SSL_read() 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 SSL_has_pending() to continue to return 1 even after an SSL_read_ex() or SSL_read() call because the buffered and unprocessed data is not yet processable (e.g. because OpenSSL has only received a partial record so far). =head1 RETURN VALUES SSL_pending() returns the number of buffered and processed application data bytes that are pending and are available for immediate read. SSL_has_pending() returns 1 if there is buffered record data in the SSL object and 0 otherwise. =head1 SEE ALSO L, L, L, L, L =head1 HISTORY The SSL_has_pending() function was added in OpenSSL 1.1.0. =head1 COPYRIGHT Copyright 2000-2016 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 L. =cut