Promotic

SetStringVar - method of the PmBuffer object

Description:
Writing the text string with variable length (terminated by the NULL character).
Syntax:
Empty SetStringVar(Long nOffset, String sValue, [Long nAttr], [Long nEncoding])
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.
sValue(String) Text string that is being written.
nAttr[optional] (Long) Additional parameters.
0 (default) - The text string is saved with the NULL character at the end.
1 - The text string is saved without the NULL ending character.
nEncoding[optional] (Long) Encoding of a text string in the data block.
0 (default) - (ANSI) Each character is stored in a single byte. The values from 0 to 127 represent an ASCII character table that is not changing in meaning. The values from 128 to 255 have different meaning in various localizations (code pages, e.g. Windows 1250).
1 - (UTF-8) Each character is stored in 1, 2 or 4 bytes, it means has variable length. The advantage is that the latin characters (ASCII) are stored in a single byte. Only special characters and characters with diacritics (i.e. national dependent characters) are stored in multiple bytes. This storage is therefore very efficient.
This encoding is commonly used for data exchange, data persistence and on the Web.
2 - (UTF-16) Each character is stored in 2 bytes (or exceptionally in 4 bytes), i.e. it has a fixed length. The advantage is that most characters are stored in 2 bytes so these strings are easy to work with (because of the fixed length).
This encoding is used internally in Windows OS, but also in the JavaScript language or .NET, because the mannipulation with these fixed strings is easier.
CodePage - Each character is stored in one or more bytes according to the specified code page (CodePage). A code page is specified by its number, which is valid across all operating systems and programs. For example 1250 for Windows 1250 or 852 for Latin 2.
Note:
This method is also functional in Web panels.
Limitations for Web panels:
nEcoding=0 (ANSI) - encoding does not work for characters with a value greater than 127
nEcoding=1 (UTF-8) - encoding does not work in Internet Explorer.
nEcoding=CodePage - encoding does not work
See also:
Example:
JavaScriptSelect and copy to clipboard

var oBuf = Pm.CreatePmBuffer();
var s1 = "Help me!";
oBuf.SetStringVar(-2, s1, 0, 1);

History:
Pm9.00.04: Created
PROMOTIC 9.0.27 SCADA system documentation MICROSYS, spol. s r.o.

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