ZCOM C I/F Library Routines
Introduction
ZLU Definition
The zlu field of a <zaddr_type> parameter specifies the ZLU address. The checksum field of a <zaddr_type> parameter is a checksum used to verify the address of the message. All routine calls that specify ‘(with checksum)’ in the ZLU definition must have both fields defined correctly for successful processing.
The checksum minimizes the possibility of messages being accidentally misdirected. The checksum is calculated based on the type and name of the ZLU, hence the checksum does not change even when the system is restarted. If the program that opened the ZLU is killed, it may reopen the same ZLU by referencing it by ZLU name and the same checksum will be generated. This allows any other message sources to deliver data to a restarted ZLU without any impact.
The node field of a <zaddr_type> parameter must contain a valid node number or zero if it is an input parameter. However, if it is a return parameter, such as in the zopen call, then the node number returned is the local node as defined in the “configuration file”. Note that specifying a node number of zero is the same as specifying the local node number. If a remote node is specified, it must be defined in the
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