BACnetStack_SendWhoHasWithObjectIdentifier

bool BACnetStack_SendWhoHasWithObjectIdentifier(
  const uint16_t objectType,
  const uint32_t objectInstance,
  const uint8_t * connectionString,
  const uint8_t connectionStringLength,
  const uint32_t networkPortInstance,
  const bool broadcast,
  const uint16_t destinationNetwork,
  const uint8_t * destinationAddress,
  const uint8_t destinationAddressLength);

Sends an unconfirmed Who-Has request identifying the object by Object-Identifier, soliciting an I-Have from any device that owns a matching object.

BACnet reference: ANSI/ASHRAE 135-2024 clause 16.9 (Who-Has and I-Have Services).

Parameters

Parameter	Direction	Description
objectType, objectInstance	in	The BACnet Object Identifier being searched for, carried as two parameters (see the API conventions).
connectionString, connectionStringLength	in	The datalink address to send TO (the destination) - not the local address to send from. For IPv4 this is 6 bytes: 4 octets of IPv4 address followed by 2 octets of port, big-endian (e.g. 0xC0,0xA8,0x01,0x05,0xBA,0xC0 = 192.168.1.5:47808; see BACnetStack_SendRegisterForeignDevice() for a worked example); on BACnet/IPv4 the stack refuses to send to a connection string of any other length, except that a broadcast from a device registered as a foreign device goes to its BBMD and does not use the connection string. MS/TP and BACnet/SC use a different connection-string shape; see their respective Set/Send exports.
networkPortInstance	in	The Network Port object instance to send the message on, or BACNET_NETWORK_PORT_DEFAULT (4194303) for the default/single port.
broadcast, destinationNetwork, destinationAddress, destinationAddressLength	in	broadcast selects a broadcast or a unicast where the data link has the choice: on BACnet/IP an Original-Broadcast-NPDU or an Original-Unicast-NPDU (a broadcast from a device registered as a foreign device goes to its BBMD as a Distribute-Broadcast-To-Network); on BACnet/SC the broadcast VMAC; on MS/TP it is ignored and connectionString decides. destinationNetwork 0 keeps the message on the local network; 1 to 65534 routes it to that network, to the device whose MAC address is destinationAddress/destinationAddressLength or, with NULL and 0 there, to every device on that network; 65535 is a global broadcast to every network.

Returns

True if the request was sent, otherwise false.

Topic: Client requests. Declared in CASBACnetStackDLL.h.