digest calculation and returns the digest value. BIO_puts() is
not supported.
-BIO_reset() reinitializes a digest BIO.
+BIO_reset() reinitialises a digest BIO.
BIO_set_md() sets the message digest of BIO B<b> to B<md>: this
must be called to initialize a digest BIO before any data is
a chain containing digest BIOs then this can be done by prepending
a buffering BIO.
+Before OpenSSL 1.0.0 the call to BIO_get_md_ctx() would only work if the BIO
+had been initialized for example by calling BIO_set_md() ). In OpenSSL
+1.0.0 and later the context is always returned and the BIO is state is set
+to initialized. This allows applications to initialize the context externally
+if the standard calls such as BIO_set_md() are not sufficiently flexible.
+
=head1 RETURN VALUES
BIO_f_md() returns the digest BIO method.