EVP_PKEY_get_int_param is not getting degree from EC key

[Blumenthal, Uri - 0553 - MITLL]

>  > But, considering that the man pages describe C API, wouldn't it be
>  > nice to mention (even though it may be obvious that a number of order
>  > 2^384 might not fit into 32 or even 64 bits) that the actual type is
>  > BIGNUM?
>
>  No, the type is not a BIGNUM. Please read "man OSSL_PARAM" it contains
>  the information on what types OSSL_PARAM support.

I did that before playing with and modifying the OP's code. Obviously, either I'm too dense to understand it, or it's too dense.

>  > Also, what should arguments to that C call EVP_PKEY_get_int_param()
>  > look like to succeed? Do I need to pass a pointer to BN there???
>
>  Please read "man EVP_PKEY_get_int_param".

See above. Some verbiage, very little clues - especially for somebody who doesn't already know how it works.

   int EVP_PKEY_get_int_param(const EVP_PKEY *pkey, const char *key_name,
                              int *out);
   EVP_PKEY_get_int_param() retrieves a key pkey integer value *out associated with a name of key_name.

Overall, VERY confusing.

How does one know (without going through EVP_PKEY_gettable_params(EVP_PKEY *pkey) and EVP_PKEY_get_params(const EVP_PKEY *pkey, OSSL_PARAM params[])) what method to use to retrieve what parameter?
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