int gnutls_openpgp_crt_get_key_usage(gnutls_openpgp_crt_t key, unsigned int * key_usage);
ARGUMENTS
gnutls_openpgp_crt_t key
should contain a gnutls_openpgp_crt_t structure
unsigned int * key_usage
where the key usage bits will be stored
DESCRIPTION
This function will return certificate's key usage, by checking the
key algorithm. The key usage value will ORed values of the:
GNUTLS_KEY_DIGITAL_SIGNATURE, GNUTLS_KEY_KEY_ENCIPHERMENT.