Promotic

LoadFromFile - method of the PmBuffer object

Description:
Reading values from binary file into the data block.
Syntax:
Long LoadFromFile(Long nOffset, String sFile, [Long nFileOffset], [Long nLength])
Parameters:
nOffset(Long) Specifies the position of written value in the data block.
The whole written item muyst be inside the data block, or the whole item is added to the end of the data block. The item is written either whole or not read at all.
>= 0 - Index (in bytes, zero-based index) in the data block.
-2 - The whole item is added to the end of the data block. The size of the data block is increased by the written item.
-4 - The internal automatic position is used (see the AutoOffset property). It points behind the last read or written value.
This operation shifts the internal automatic position behind the read/written value.
If the items are read/written one by one then it is not necessary to define the position manually, but it is better to use this automated positioning.
sFile(String) The file name with the path.
If a full path is not entered, then it is completed relative to the application folder.
It is recommended to use the PROMOTIC path syntax - see PROMOTIC path to files and folders.
nFileOffset[optional] (Long) Specifies the position of read value in the binary file in bytes.
The 0 value (default) means reading from beginning of the file.
nLength[optional] (Long) Specifies the number of read bytes.
The -1 value (default) means reading to the end of the file.
Return value:
Returns the number of really read bytes
Note:
This method is not functional in Web panels.
See also:
Example:
Reading from the file. For inverse example see Example.
JavaScriptVBScriptSelect and copy to clipboard

var oBuf = Pm.CreatePmBuffer();
oBuf.LoadFromFile(-2, "#data:Test.bin", 0, -1);
oBuf.AutoOffset = 0;
Pm.Debug("GetInt16=" + oBuf.GetInt16(-4));
Pm.Debug("GetInt8=" + oBuf.GetInt8(-4));
Pm.Debug("Hex=" + oBuf.GetHexaString(0));

History:
Pm9.00.05: Created
PROMOTIC 9.0.27 SCADA system documentation MICROSYS, spol. s r.o.

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