How to get Chain of certificates in X509_STORE_CTX object as X509 objects in C code

How to get Chain of certificates in X509_STORE_CTX object as X509 objects
in C code

I want to get access to all certificates from a X509_STORE_CTX object
using openssl C code.
I can get a single certificate like this ctx->cert if I have a pointer to
a X509_STORE_CTX object (X509_STORE_CTX *ctx ) but if there is a chain how
can I get a list of all as X509 objects.
Thanks