=head1 NAME
-BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl - BIO control operations
+BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset,
+BIO_flush, BIO_eof, BIO_set_close, BIO_get_close, BIO_pending,
+BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending, BIO_get_info_callback,
+BIO_set_info_callback - BIO control operations
=head1 SYNOPSIS
internal buffers but it is not possible to determine this in a
portably way. For other types of BIO they may not be supported.
+Filter BIOs if the do not internally handle a particular BIO_ctrl()
+operation usually pass the operation to the next BIO in the chain.
+This often means there is no need to locate the required BIO for
+a particular operation, it can be called on a chain and it will
+be automatically passed to the relevant BIO.
+
+Source/sink BIOs will return an error if the do not recognise the
+BIO_ctrl() operation.
+
=head1 SEE ALSO
TBA