A surprise after 18 years of WinCC OA

[fmulder]

One of the nice things of OA is the possibility to play with data types. Assign an int to a string, an int to string etc.. It is often quite usefull that you do not really think about data types and just assign them as you wish.

I'm sure (or at least I hope so ) that you all, at some time, have assigned a string to a boolean. Example:

* You read a value 'false' from a file or database
* and then just assign it to a boolean

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string conditionFromFile = FileRead( ... )
bool bCondition = conditionFromFile ;

Todat, one of my colleagues types the magic word 'False' in a database with an effect that suprised me. I then wrote the following small script to demonstrate.

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main()
{
  DebugN( "False -> " + (bool)"False" );
  DebugN( "false -> " + (bool)"false" );
  DebugN( "True -> " + (bool)"True" );
  DebugN( "true -> " + (bool)"true" );
}   

The result in the LogViewer ?

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WCCOAui1:["False -> TRUE"]     <== !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
WCCOAui1:["false -> FALSE"]
WCCOAui1:["True -> TRUE"]
WCCOAui1:["true -> TRUE"]

I can't this a bug because we all know that I should have checked the string. Still, I've assigned string to integers, floats and booleans for years and never realised this behavior

Hope it helps someone

share the fun
Frenk Mulder

[kilianvp]

Casting "FALSE" or "false" work as expected. Everything else has always been true. Just do strtolower or strtoupper. It's similar in other languages! I did my Tests in 3.12 and 3.18

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main()
{
  // works as intended
  DebugN( "0 -> " + (bool)"0" );
  DebugN( "1 -> " + (bool)"1" );
  DebugN( "false -> " + (bool)"false" );
  DebugN( "FALSE -> " + (bool)"FALSE" );
  DebugN( "true -> " + (bool)"true" );
  // always true
  DebugN( "3 -> " + (bool)"3" );
  DebugN( "False -> " + (bool)"False" );
  DebugN( "True -> " + (bool)"True" );
  DebugN( "winccoa -> " + (bool)"winccoa" );
}

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WCCOAui0:["0 -> FALSE"]
WCCOAui0:["1 -> TRUE"]
WCCOAui0:["false -> FALSE"]
WCCOAui0:["FALSE -> FALSE"]
WCCOAui0:["true -> TRUE"]
WCCOAui0:["3 -> TRUE"]
WCCOAui0:["False -> TRUE"]
WCCOAui0:["True -> TRUE"]
WCCOAui0:["winccoa -> TRUE"]