man BIO_f_null () - null filter
NAME
BIO_f_null - null filter
SYNOPSIS
#include <openssl/bio.h>
BIO_METHOD * BIO_f_null(void);
DESCRIPTION
BIO_f_null() returns the null filter BIO method. This is a filter BIO that does nothing.
All requests to a null filter BIO are passed through to the next BIO in the chain: this means that a BIO chain containing a null filter BIO behaves just as though the BIO was not there.
NOTES
As may be apparent a null filter BIO is not particularly useful.
RETURN VALUES
BIO_f_null() returns the null filter BIO method.
SEE ALSO
TBA