(gss_cred_id_t, read) A handle that refers to the
target credential. Specify GSS_C_NO_CREDENTIAL to inquire about
the default initiator principal.
gss_name_t * name
(gss_name_t, modify, optional) The name whose identity the
credential asserts. Storage associated with this name should be
freed by the application after use with a call to
gss_release_name(). Specify NULL if not required.
OM_uint32 * lifetime
(Integer, modify, optional) The number of seconds for
which the credential will remain valid. If the credential has
expired, this parameter will be set to zero. If the
implementation does not support credential expiration, the value
GSS_C_INDEFINITE will be returned. Specify NULL if not required.
gss_cred_usage_t * cred_usage
(gss_cred_usage_t, modify, optional) How the
credential may be used. One of the following: GSS_C_INITIATE,
GSS_C_ACCEPT, GSS_C_BOTH. Specify NULL if not required.
gss_OID_set * mechanisms
(gss_OID_set, modify, optional) Set of mechanisms
supported by the credential. Storage associated with this OID
set must be freed by the application after use with a call to
gss_release_oid_set(). Specify NULL if not required.
Obtains information about a credential.
`GSS_S_COMPLETE`: Successful completion.
`GSS_S_NO_CRED`: The referenced credentials could not be accessed.
`GSS_S_DEFECTIVE_CREDENTIAL`: The referenced credentials were invalid.
`GSS_S_CREDENTIALS_EXPIRED`: The referenced credentials have
expired. If the lifetime parameter was not passed as NULL, it will
be set to 0.