Promotic

ReadFromSocketEx - method of the PmaData object

Description:
It is an extension of the ReadFromSocket method.
Syntax:
Boolean ReadFromSocketEx(Long nType, Long nSubType, Long nFrom, Long nCount)
Parameters:
nType(Long) Subtype of the data protocol.
nSubType(Long) Version of the data protocol subtype.
nFrom(Long) Index (zero-based index) of the variable in the PmaData object. From this variable (including) the data is received.
nCount(Long) The number of variables in the object that are received.
Return value:
true - The method successfully queued the request for reading from server. After data transfer the onEndOfTransfer event is triggered.
false - The method hasn't queued the request for reading data. Probably the previous message about sending/receiving by sockets of this object hasn't been finished yet. The onEndOfTransfer event is not triggered.
Note:
This method is not functional for PmFree.

It allows the user to specify the subtype of the data protocol by which will communicate it with the server and for example the value and number of values of the PmaData object from which the data received from the network will be written into the object. The exact meaning of the nFrom and nCount parameters can depend on the nType and nSubType parameters.

Supported subtypes of the protocol:

nType nSubType meaning
0 0 protocol for transmission of the whole PmaData object. Parameters nFrom and nCount are ignored.
1 1 this allows to enter by the nFrom and nCount parameters from which value and how many values of the object have to be received.


The method only activates the data transfer but there is no assurance that data are already transferred after ending this method. The data transfer termination is announced by the the onEndOfTransfer event.
Calling this method is meaningful only if the "Sockets" tab is configured as Socket client.
Variables on the "Data" tab of this object are filled up by the incoming data.
See also:
Example:
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var oData = pMe.Pm("/Data");
oData.ReadFromSocketEx(1, 1, 0, 3);
// or
var bDone = oData.ReadFromSocketEx(1, 1, 0, 3);   // bDone = true or false
PROMOTIC 9.0.27 SCADA system documentation MICROSYS, spol. s r.o.

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