I'm currently working on implementing EVP_PKEY_cmp for ruby's openssl wrapper.
Initially, I was going by the documentation provided for EVP_PKEY_cmp, but the maintainer discovered conflicting documentation.
States the following:
The param_cmp() method compares the parameters of keys a and b. It MUST return 1 when the keys are equal, 0 when not equal, or a negative number on error. It's called by EVP_PKEY_cmp_parameters(3).
However
States something slightly different:
The function EVP_PKEY_cmp_parameters() and EVP_PKEY_cmp() return 1 if
the keys match, 0 if they don't match, -1 if the key types are different
and -2 if the operation is not supported.
At this point I'm explicitly checking the type on each and not able to check -2 against a 'not supported' or in ruby 'not implemented' exception given EVP_PKEY_ASN1_METHOD(3) states ANY negative number can be an error.
The current work in progress can be found here if interested.
Thanks,
Colton
