BACnetStack_SendWhoAmI

bool BACnetStack_SendWhoAmI(
  const uint16_t vendorId,
  const char * modelName,
  const uint32_t modelNameLength,
  const char * serialNumber,
  const uint32_t serialNumberLength,
  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 modelNameEncoding,
  const uint8_t serialNumberEncoding);

Sends an unconfirmed Who-Am-I request (cl. 16.11, unconfirmed-service-choice 13).

A device uses this to announce its vendorId / modelName / serialNumber, typically to solicit a You-Are that assigns its device instance. When such a You-Are arrives, the stack asks the host through the callback registered with BACnetStack_RegisterCallbackSetPropertyObjectIdentifier() before applying the new instance.

Returns false if Who-Am-I / You-Are support was not compiled (STACK_OPTION_WHO_AM_I_YOU_ARE).

BACnet reference: ANSI/ASHRAE 135-2024 clause 16.11 (Who-Am-I and You-Are Services); clause 19.7 (Unconfigured Device Discovery and Address Assignment).

Parameters

Parameter	Direction	Description
`vendorId`	in	The BACnet vendor identifier of this device.
`modelName, modelNameLength`	in	The device model name and its length.
`serialNumber, serialNumberLength`	in	The device serial number and its length.
`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.
`modelNameEncoding, serialNumberEncoding`	in	The character set (cl. 20.2.9) the strings are encoded in: 0 = UTF-8, 1 = IBM/Microsoft DBCS, 2 = JIS C 6226, 3 = ISO 10646 (UCS-4), 4 = ISO 10646 (UCS-2), 5 = ISO 8859-1.

Returns

True if the request was sent; false on a missing send callback / connection string or a build failure.

Topic: Client requests. Declared in CASBACnetStackDLL.h.