another vector question

This is a discussion on another vector question within the C++ Programming forums, part of the General Programming Boards category; ok, now I need to get an actual pointer to the data in a vector, I have to pass this ...

  1. #1
    Malum in se abachler's Avatar
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    another vector question

    ok, now I need to get an actual pointer to the data in a vector, I have to pass this to a function that only accepts raw pointers.
    Until you can build a working general purpose reprogrammable computer out of basic components from radio shack, you are not fit to call yourself a programmer in my presence. This is cwhizard, signing off.

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    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by abachler View Post
    ok, now I need to get an actual pointer to the data in a vector, I have to pass this to a function that only accepts raw pointers.
    Code:
    &vec[0]

  3. #3
    Malum in se abachler's Avatar
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    so if I have -

    Code:
    string Foo;
    I can just pass

    Code:
    MyFunction((LPVOID)&Foo);
    and that will point to the characters int eh string themselves?
    Until you can build a working general purpose reprogrammable computer out of basic components from radio shack, you are not fit to call yourself a programmer in my presence. This is cwhizard, signing off.

  4. #4
    Banned master5001's Avatar
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    Not even remotely...

    Example:
    Code:
    MyFunction((LPCVOID)Foo.c_str());

  5. #5
    The larch
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    It seems that string (currently) doesn't really allow non-constant access to the internal buffer (it is not required to be contiguous). You can use a vector<char> instead of string.
    I might be wrong.

    Thank you, anon. You sure know how to recognize different types of trees from quite a long way away.
    Quoted more than 1000 times (I hope).

  6. #6
    C++まいる!Cをこわせ! Elysia's Avatar
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    Pointers needn't be cast to void* in either C or C++ either.
    Also there's no such thing as LPCVOID
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  7. #7
    Banned master5001's Avatar
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    The only reason I put the cast was to assure that the OP was aware of the fact that std::string::c_str() is constant. Hence the LPCVOID.

  8. #8
    C++まいる!Cをこわせ! Elysia's Avatar
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    There is no such thing as LPCVOID. I think it's just better to write const void*.
    All those LP* defines/typedefs are evil anyway. They obfuscate code, makes it harder to read and more prone to errors.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  9. #9
    Cat without Hat CornedBee's Avatar
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    Whether you like them or not, to say that they don't exist is absurd, and totally irrelevant to the thread, too.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

  10. #10
    C++まいる!Cをこわせ! Elysia's Avatar
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    I said "LPCVOID" didn't exist. Unless you typedef that one yourself, it doesn't exist in any common windows header.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  11. #11
    Cat without Hat CornedBee's Avatar
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    OK, you're right. Sorry.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

  12. #12
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    Quote Originally Posted by Elysia View Post
    I said "LPCVOID" didn't exist. Unless you typedef that one yourself, it doesn't exist in any common windows header.
    http://msdn2.microsoft.com/en-us/library/aa383751(VS.85).aspx

    WinDef.h

  13. #13
    C++まいる!Cをこわせ! Elysia's Avatar
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    News to me. Never seen it before that I can remember.
    But... I stand corrected.
    Although, const void* is much easier to read and interpret rather than LPCVOID. I still stand fast to that.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  14. #14
    Cat without Hat CornedBee's Avatar
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    And I grepped the wrong directory in my search.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

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    Quote Originally Posted by Elysia View Post
    News to me. Never seen it before that I can remember.
    But... I stand corrected.
    Although, const void* is much easier to read and interpret rather than LPCVOID. I still stand fast to that.
    i am hearing such comments from someone who uses cryptic (to me, at least ) #defines to make it even more difficult to understand template ridden code

    but anyways such typedefs have advantages:
    like:
    Code:
    char* p, q r; // not all are pointers :(
    LPSTR p, q, r; // all are pointers :)

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