+/**
+ * \par Description:
+ * Creates a client identification string with given method. Client is a process identified by the
+ * unique name at the other side of the dbus connection.
+ *
+ * \par Purpose:
+ * Client identification string is required for cynara_check() and cynara_async_check() functions.
+ *
+ * \par Typical use case:
+ * The function is called before the call of one of ...check() functions.
+ * Returned string is used as client parameter in ...check() function.
+ * String is released with free() function when it is no longer needed.
+ *
+ * \par Method of function operation:
+ * The function generates client string by calling a method from DBus Interface
+ * ("org.freedesktop.DBus") which is placed on system bus ("org.freedesktop.DBus").
+ *
+ * \par Sync (or) Async:
+ * This is a synchronous API.
+ *
+ * \par Thread safety:
+ * This function is NOT thread-safe. If functions from described API are called by multithreaded
+ * application from different threads, they must be put into mutex protected critical section.
+ *
+ * \par Important notes:
+ * Memory for returned client string is obtained with malloc(), and should be freed with free().
+ * Allocated string is returned only, when function succeeds.
+ *
+ * \param[in] connection DBus connection to a bus. It manages incomming and outgoing messages
+ * \param[in] uniqueName DBus identifier of the client
+ * \param[in] method Method of client identifier creation
+ * \param[out] client Placeholder for allocated string containing client id
+ *
+ * \return CYNARA_API_SUCCESS on success
+ * CYNARA_API_INVALID_PARAM when client is NULL or uniqueName or client has wrong
+ * value (i.e NULL or non-existing)
+ * CYNARA_API_METHOD_NOT_SUPPORTED when requested method is not supported
+ * CYNARA_API_OUT_OF_MEMORY when there was error allocating memory
+ */
+int cynara_creds_dbus_get_client(DBusConnection *connection, const char *uniqueName,
+ enum cynara_client_creds method, char **client);
+
+/**
+ * \par Description:
+ * Creates a user identification string with given method. User is an executor of process
+ * at the other side of socket.
+ *
+ * \par Purpose:
+ * User identification string is required for cynara_check() and cynara_async_check() functions.
+ *
+ * \par Typical use case:
+ * The function is called before the call of one of ...check() functions.
+ * Returned string is used as user parameter in ...check() function.
+ * String is released with free() function when it is no longer needed.
+ *
+ * \par Method of function operation:
+ * The function generates user string by calling a method from DBus Interface
+ * ("org.freedesktop.DBus") which is placed on system bus ("org.freedesktop.DBus").
+ *
+ * \par Sync (or) Async:
+ * This is a synchronous API.
+ *
+ * \par Thread safety:
+ * This function is NOT thread-safe. If functions from described API are called by multithreaded
+ * application from different threads, they must be put into mutex protected critical section.
+ *
+ * \par Important notes:
+ * Memory for returned user string is obtained with malloc(), and should be freed with free().
+ * Allocated string is returned only, when function succeeds.
+ *
+ * \param[in] connection DBus connection to a bus. It manages incomming and outgoing messages
+ * \param[in] uniqueName DBus identifier of the client invoked by the user
+ * \param[in] method Method of client identifier creation
+ * \param[out] user Placeholder for allocated string containing user id
+ *
+ * \return CYNARA_API_SUCCESS on success
+ * CYNARA_API_INVALID_PARAM when user is NULL or connection is not valid DBus connection or
+ * uniqueName does not represent a process conected to the DBus
+ * CYNARA_API_METHOD_NOT_SUPPORTED when requested method is not supported
+ * CYNARA_API_OUT_OF_MEMORY when there was error allocating memory
+ */
+int cynara_creds_dbus_get_user(DBusConnection *connection, const char *uniqueName,
+ enum cynara_user_creds method, char **user);
+
+/**
+ * \par Description:
+ * Return PID of a proces identified by the unique name at the other side of the dbus connection.
+ *
+ * \par Purpose:
+ * PID may be used for client_session creation with cynara_helper_session_from_pid() function
+ * from libcynara-helper-session library. Client_session is needed for cynara_check()
+ * and cynara_async_check() functions.
+ *
+ * \par Typical use case:
+ * The function is called before the call of cynara_helper_session_from_pid() function.
+ *
+ * \par Method of function operation:
+ * The function reads PID of the peer by calling a method from DBus Interface
+ * ("org.freedesktop.DBus") which is placed on system bus ("org.freedesktop.DBus")
+ * with "GetConnectionUnixProcessID" argument.
+ *
+ * \par Sync (or) Async:
+ * This is a synchronous API.
+ *
+ * \par Thread safety:
+ * This function is NOT thread-safe. If functions from described API are called by multithreaded
+ * application from different threads, they must be put into mutex protected critical section.
+ *
+ * \param[in] connection DBus connection to a bus. It manages incomming and outgoing messages
+ * \param[in] uniqueName DBus identifier of the client invoked by the user
+ * \param[out] pid Placeholder for PID returned by function
+ *
+ * \return CYNARA_API_SUCCESS on success
+ * CYNARA_API_INVALID_PARAM when socket_fd is not valid connected socket descriptor
+ * CYNARA_API_UNKNOWN_ERROR when system function fails in incredible situation
+ * CYNARA_API_OUT_OF_MEMORY when there was error allocating memory
+ */
+int cynara_creds_dbus_get_pid(DBusConnection *connection, const char *uniqueName, pid_t *pid);