returning string value

This is a discussion on returning string value within the Windows Programming forums, part of the Platform Specific Boards category; Hi All, I try to write simply WinGUI dialog that collects user input and returns it to calling program. But ...

  1. #1
    vn1
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    Question returning string value

    Hi All,

    I try to write simply WinGUI dialog that collects user input and returns it to calling program. But I see that WinMain could return only int
    How can I return and get string (char) value?

    Any help will be appreciated
    Vaidotas.Vilnius.lt

  2. #2
    It's full of stars adrianxw's Avatar
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    When WinMain returns, it returns it's value to the operating system and terminates the program. The international C++ standard requires that your "main" returns an integer. If you want to return something other than that, I would suggest you have a design problem, or have not explained your question!

    Welcome, by the way, we do not get many visitors from the Baltic republics.
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    Registered User johnnie2's Avatar
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    Just so you know, that 32-bit int returned from WinMain() is four bytes, and a pointer to a char array is also four bytes.
    "Optimal decisions, once made, do not need to be changed." - Robert Sedgewick, Algorithms in C

  4. #4
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    johnnie2,

    thanks for your idea.
    But how to retain char array in memory to be available for calling program? I suppose to use ShellExecute or something like for calling...

    (Adrian, I know that my straightforward approach is bad, I just ask about ways usually applied)

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    vn1
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    Sorry, Unregistered post was mine.
    Vaidotas.Vilnius.lt

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    As said
    >>If you want to return something other than that, I would suggest you have a design problem, or have not explained your question!

    a DLL would be better if you need a seperate interface. Send it the string to fill in.
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    It's full of stars adrianxw's Avatar
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    If you are working within a subprocess, you could probably use SendMessage() to send the contents of your string back to it's parent.
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  8. #8
    Davros
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    The simplest (and crudest) way of returning data from a program is to get the program to write the data into a temporary file before it terminates. The calling process can then read the file.

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    It's full of stars adrianxw's Avatar
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    >>> The simplest (and crudest)

    True of course, but then the writing program would need to tell the reading program that the data had been written. Messy - part written files, old files from previous runs, etc....

    Yup, can be done, but is not a real option in a rtue multitasking OS environment.
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    Registered User johnnie2's Avatar
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    Elaborating on an earlier response, you could use FindWindow() to locate your parent window and send a WM_COPYDATA message, which apparently exists especially for this situation.

    Another possibility is the clipboard.
    "Optimal decisions, once made, do not need to be changed." - Robert Sedgewick, Algorithms in C

  11. #11
    vn1
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    Yes, thanks a lot, now I see - WM_COPYDATA message is right method when I have C++ or VB apps on both sides.

    Besides I wonder whether it's possible to write application which sends a message/string into VBScript? Maybe I should create COM Automation object for this purpose or can someone mention another way?
    Vaidotas.Vilnius.lt

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