Reg. type of certificate - CA / EE based on X509_check_ca().

[Sanjaya Joshi]

Hello,
  My application uses openssl 1.0.0, and it uses X509_check_ca() to find
out if an X509 certificate is a CA certificate, or an End-entity (EE)
certificate.

The below are the possible return codes.

        /* return codes of X509_check_ca():
        * 0 not a CA
        * 1 is a CA
        * 2 basicConstraints absent so "maybe" a CA
        * 3 basicConstraints absent but self signed V1.
        * 4 basicConstraints absent but keyUsage present and keyCertSign
asserted.
        */

My question here is, if we get return code as 4, should we consider this as
a CA certificate or an EE certificate ?

Any quick support in this regard is much appreciated.
Regards,
Sanjaya