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8 recv% function – Rockwell Automation 57C610 Enhanced Basic Language, AutoMax User Manual

Page 117

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8Ć7

8.8

RECV% Function

Format:

RECV%( sn%, var, len% )

where:

sn%

is the number of the socket through which the

message is to be received. This is the value that

was returned from the SOCKET% or ACCEPT%

function. This can be specified as a simple variable

or as an element of an array.

var

is the variable where the data received is written. It

can be a boolean, integer, double integer, real,

string, or an array of those types. If an array is

specified, no subscript may be given.

len%

is the number of bytes to receive. This parameter

can be a constant, an integer, or a double integer.
If var is a simple variable and len% is greater than

the size of the simple variable, then var must be

defined as I/O to avoid overwriting AutoMax

memory.
If var is an array, and len% is zero, the length to

receive is the size of the array. An error is

generated if len% is greater than the size of the

array.
For TCP only, if len% is -1, the number of bytes

received will be returned to the sender.

This function writes up to len% bytes of data from socket SN% into

the variable VAR.
If a TCP socket is specified, it must be connected.
A socket can be selected as blocking or nonĆblocking. If the socket

is blocking and no data has come in, the task will be suspended

until data arrives. If the socket is nonĆblocking and no data has

come in, the RECV% command will return with the error No

message waiting. The default mode is blocking.
Values Returned:
>0

Length of message received

-2

ENI not initialized

-9

No buffer space

-15 Bad socket number

-17 Message too long

-18 Zero length for nonĆarray

-26 Array is not single dimension

-29 Max size of strings are not equal

-31 Max size of string < recv size of string

-32 Beyond end of array

-101 No message waiting

-102 Socket not connected
For example:

RECV_LEN% = RECV%( SN%, SET_POINTS%, LEN%)

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