in reply to Re^5: Perl program calling external .dll functions
in thread Perl program calling external .dll functions

I didn't use hardcoded address 123456789

That's not a hardcoded address, just a string containing numbers.

or ' '. (Is that a weird way of saying NULL?)

Again, just a string containing four spaces.

He really is being unclear if he can't even communicate which language's class he's talking about.

Agreed. Reading between the lines, I'd guess that he's not a C++ programmer, and all he has is a VB example he's attempting to interpret.

, it doesn't say anything about the structure of the type, necessary knowledge for building an instance of one.

I've never used VB, but looking at the linked article I guess that the VB String type is compatible with c/C++ char*.

I can't test anything because my 32-bit perl Win32::API setup is broken. Maybe this info will help you help him.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^7: Perl program calling external .dll functions
by ikegami (Patriarch) on Mar 18, 2011 at 15:33 UTC

    That's not a hardcoded address, just a string containing numbers.

    No way. "L" does not create a string.

    I've never used VB, but looking at the linked article I guess that the VB String type is compatible with c/C++ char*.

    Then he would just have to use "P".

[reply]
      No way. "L" does not create a string.

      Obviously, but if he knew how to do it, he wouldn't have to ask the question.

      Given the "String" in the supplied prototype, I rather more inclined to think he intended to pass '123456789' as a string, but used the wrong parameter code (L rather than P), rather than believe that he intended that a string of ascii decimals would be converted to a number and encoded as a pointer. To...something?

      Aren't you?

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

        Of course I still think "L" is wrong. ("Whatever it is, it's definitely not a uint32_t as you're telling Win32::API it is.") You're the only one who suggested otherwise. ("Passed by reference this would render an address, which on a 32-bit platform will usually come through successfully as a 32-bit numeric.")

        I'm inclined to think it's neither of the options you presented, though. C++ does have a class named String. Waiting on the OP for clarification. (Upd: Oops, it's actually "string" (in the "std" namespace). )

        If he does mean C++'s String, I doubt the layout of the class is defined. A portable solution would be impossible without processing the appropriate .h file. That's why I recommended Inline::CPP.

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