Function for sending a UDP message with notification to a previously specified station.
The message mandatorily includes a response, which must be read via the udp_recv_notify() function. The function can be used only for communication from the client.
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i32 udp_send_notify (i32 idx, buff, i32 buffLen)
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UDP communication handler number
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Generic buffer containing the data packet to be transmitted. It can be a string variable, a struct_p (packed structure), or an array of struct_p. In the case of struct_p, the variable must be declared global.
In the struct, the first member must be declared of type u32 and represents the message identifier msgId; the value is assigned by the udp_send_notify() function. msgId must be used server-side in the response message and is used to ensure routing to the correct client. All other data is for user use.
The maximum size of this structure is: MAX_UDP_DATA=508 bytes
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Number of total bytes to be transmitted (including msgId)
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Returns:
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>= 0
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Operation performed successfully. The number of characters sent is returned
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-1
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Illegal idx
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-2
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Socket not open
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-3
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Socket open as server and not as client
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-4
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buffLen greater than maximum allowed
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-5
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An udp_send_notify() already in progress for the specified idx
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-1000 -:- -2000
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Error code of the S.O. function sendto(), with offset 1000
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To see some returned errors more specifically, see Returned Error Table
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Rule, Task
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Only one udp_send_notify() function can be active simultaneously toward each server (i.e., for each open idx)
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For a concrete example see in the RDE environment: Workspace -> Specials -> Examples Library.
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-1009
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[EBADF] Id invalid
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-1011
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[EAGAIN or EWOULDBLOCK] Retry. The socket was non-blocking and receiving would block execution, or a timeout on receiving was imposed and that timeout expired before any data was received
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-1013
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[EACCES] The SO_BROADCAST option was not imposed on the socket and an address set is broadcast type
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-1014
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[EFAULT] The buffer pointer points to an area of memory outside the process space
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-1022
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[EINVAL] The total I/O length is greater than the maximum that can be represented by the returned type
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-1032
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[EPIPE] The socket has lost connection
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-1088
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[ENOTSOCK] Invalid id, does not refer to a socket
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-1089
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[EDESTADDRREQ] In an unconnected socket, the address was not specified
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-1097
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[EAFNOSUPPORT] The address specified in the address family cannot be used by this socket
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-1105
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[ENOBUFS] The message was not sent because it would have exceeded the maximum buffer size
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-1106
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[EISCONN] A destination address was specified and the socket is already connected
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-1112
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[EHOSTDOWN] The destination is a host on the local subnet and does not respond to the ARP protocol
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-1113
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[EHOSTUNREACH] Destination not reachable
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-1122
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[EMSGSIZE] Message too long
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NOTE: For the complete table of error codes see Error codes functions paying attention at the offset.
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