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Thread: Strange behavior on Wine/Linux

  1. #1

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    Strange behavior on Wine/Linux

    Code:
    double d = 0;
    string s = "";  // Empty string
    
    if (double.TryParse(s, out d) == true)
    {
        if (d.ToString() == "")
        {
            MessageBox.Show("Is Empty String");
        }
    }
    The code seems quite straight forward. The string s is empty so the tryparse should fail. On Windows it does and the messagebox is never shown.

    But in an c# application in Wine the tryparse is true and, somehow, d is empty. (ie d is not zero, not even null. simply empty) and the messagebox shows.

    How is that?

    Any other strange things I need to be aware of while making my app compatible with Wine?

    Thanks

  2. #2
    Frenzied Member PlausiblyDamp's Avatar
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    Re: Strange behavior on Wine/Linux

    When you say d is "empty" what exactly do you mean? A variable of type double can't be empty, it is a value type and it should always contain something!

  3. #3

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    Re: Strange behavior on Wine/Linux

    Quote Originally Posted by PlausiblyDamp View Post
    When you say d is "empty" what exactly do you mean? A variable of type double can't be empty, it is a value type and it should always contain something!
    Exactly. I agree. It "Must" always have a value. That's the reason for my question.

    Did you look at my code? Look at the line if (d.ToString() == "") That MessageBox should never show because d can not be empty. But when running on Wine/Linux the messagebox always shows if s is an empty string.

    Remember, I'm talking about a c# (Net4) application running in 'Wine' on Linux. On Windows it behaves as expected. d is never empty. But on Linux it is empty.

  4. #4

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    Re: Strange behavior on Wine/Linux

    What I'm saying is that double.TryParse("", out d) (empty string) should return false. So that next line should never execute.

    On Windows the tryparse correctly returns false. But running that code on Wine/Linux that TryParse returns true even though we're tryparsing an empty string into a double. That's the first bug.
    But then, as you said, d can not be empty so the result of d.ToString() should not be empty. But it is.

  5. #5
    Frenzied Member PlausiblyDamp's Avatar
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    Re: Strange behavior on Wine/Linux

    I genuinely would have no idea where to go from there, if something as fundamental as double.TryParse and even a double itself isn't working correctly then I wouldn't have much faith in anything working right.

    Are there other places in the app where this works or is this the only place you are using this code?

  6. #6

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    Re: Strange behavior on Wine/Linux

    Quote Originally Posted by PlausiblyDamp View Post
    I genuinely would have no idea where to go from there, if something as fundamental as double.TryParse and even a double itself isn't working correctly
    then I wouldn't have much faith in anything working right.

    Are there other places in the app where this works or is this the only place you are using this code?
    I have quite a large database application that currently only intended for MS Windows. I was just curious about how much work would be needed to make it work in Wine on Linux.
    I was surprised to find the application works quite well. I had to remove some assumptions about Windows Fonts and I couldn't get oleDb/Jet working but the app can use MySQL anyway. Apart from that, it seems to work fine and very fast. Almost as fast as on a proper windows machine.

    But I make use of a c# function that converts a string to a number. Similar to the VisualBasic Val() function.


    Code:
    public static double Val(string s)
    {
        if (s == "") return 0;  // This line is only necessary when running in Wine/Linux
    
        double d = 0;
        if (double.TryParse(s, out d) == true) 
            return d; 
        else
            return 0;   
    
    }
    But for Wine Linux I had to add that first line that checks for an empty string otherwise it goes wrong.

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