NAME
SSL_pending —
obtain number of readable bytes
buffered in an SSL object
SYNOPSIS
#include
<openssl/ssl.h>
int
SSL_pending(const
SSL *ssl);
DESCRIPTION
Data is received in whole blocks known as records from the peer. A whole record is processed, for example decrypted, in one go and is buffered until it is read by the application via a call to SSL_read(3).
SSL_pending()
returns the number of bytes which are available inside
ssl for immediate read.
SSL_pending()
takes into account only bytes from the TLS/SSL record that is currently
being processed (if any). If the ssl->read_ahead
flag is set (see
SSL_CTX_set_read_ahead(3)), additional protocol bytes beyond
the current record may have been read containing more TLS/SSL records. This
also applies to DTLS. These additional bytes will be buffered 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 the library 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).
RETURN VALUES
SSL_pending() returns the number of
buffered and processed application data bytes that are pending and are
available for immediate read.
SEE ALSO
BUGS
Up to OpenSSL 0.9.6, SSL_pending() did not
check if the record type of pending data is application data.