[mbed-tls] Appending a cert to mbedtls_x509_crt

Hello,

I have an implementation in OpenSSL and am trying to recreate it using MbedTLS. One of the differences in these two I have yet to overcome is the following:

Is there a way to treat mbedtls_x509_crt simply as a certificate store? Say I have some PEM data, parse it into a temporary mbedtls_x509_crt and then I would like to append this certificate to said mbedtls_x509_crt certificate store.

The following is stated in the docs of mbedtls_x509_crt:

struct mbedtls_x509_crt *next

Next certificate in the linked list that constitutes the CA chain. NULL indicates  the end of the list. Do not modify this field directly.

Is there a way to achieve this if it's advised not to modify the field directly? Thank you in advance, Roman.