BACnetStack_SendWhoHasWithObjectName

bool BACnetStack_SendWhoHasWithObjectName(
  const char * objectName,
  const uint32_t objectNameLength,
  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,
  const uint8_t objectNameEncoding);

Sends an unconfirmed Who-Has request identifying the object by Object_Name, 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
objectName	in	The object name to search for. A NULL objectName returns false and sends nothing.
objectNameLength	in	The exact byte count of objectName. The name is taken by pointer-and-length, not by strlen, so embedded NUL bytes are preserved and sent.
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.
objectNameEncoding	in	The character set objectName is encoded in (135-2024 cl. 20.2.9): 0 = ANSI X3.4/UTF-8, 1 = IBM/Microsoft DBCS, 2 = JIS X 0208, 3 = ISO 10646 UCS-4, 4 = ISO 10646 UCS-2, 5 = ISO 8859-1. A non-UTF-8 encoding changes byte-level matching on the peer - a device whose Object_Name is encoded differently than what you pass here will not match.

Returns

True if the request was sent, otherwise false.

Topic: Client requests. Declared in CASBACnetStackDLL.h.