EVP_PKEY_get_group_name - get group name of a key

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       Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance
       with the License.  You can obtain a copy in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.

3.5.0                                              2025-06-04                      EVP_PKEY_GET_GROUP_NAME(3SSL)

EVP_PKEY_get_group_name() fills in the group name of the pkey into gname, up to at most gname_sz bytes
       including the ending NUL byte and assigns *gname_len the actual length of the name not including the NUL
       byte, if pkey's key type supports it.  gname as well as gname_len may individually be NULL, and won't be
       filled in or assigned in that case.

       This function was added in OpenSSL 3.0.

       EVP_PKEY_get_group_name - get group name of a key

       Among the standard OpenSSL key types, this is only supported for DH, EC and SM2 keys.  Other providers
       may support this for additional key types.

EVP_PKEY_get_group_name() returns 1 if the group name could be filled in, otherwise 0.

        #include <openssl/evp.h>

        int EVP_PKEY_get_group_name(EVP_PKEY *pkey, char *gname, size_t gname_sz,
                                    size_t *gname_len);