[MSVC] Is it valid to link against an import .lib generated from an executable?

This is a discussion on [MSVC] Is it valid to link against an import .lib generated from an executable? within the C++ Programming forums, part of the General Programming Boards category; Hi, I want to share some code which is defined inside a module from which I build an .exe. I ...

  1. #1
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    [MSVC] Is it valid to link against an import .lib generated from an executable?

    Hi,

    I want to share some code which is defined inside a module from which I build an .exe. I want to reuse it in another .Exe

    I know, the correct way is to factor it out into an extra lib and link it to both modules.

    I discovered, that I can export the needed symbols from the .exe through a .def file, just like as it where an DLL and link it to the other exe. It compiles flawlessly. At runtime it crashes with a memory read error once it touches the linked code. So probably it's not valid what I try to do. Maybe someone is able to explain why it crashes?

    Thank you!

  2. #2
    Malum in se abachler's Avatar
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    Run time linking needs to use a DLL not a LIB. LIB's need to be fixed up before they are executable.
    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.

  3. #3
    C++まいる!Cをこわせ! Elysia's Avatar
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    I don't think you can "load" an exe, can you?
    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.

  4. #4
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    Using Loadlibrary()? Hm, I can try it later...

  5. #5
    C++まいる!Cをこわせ! Elysia's Avatar
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    Well, you either need a .lib file or do a LoadLibrary to load the actual functions into memory.
    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.

  6. #6
    Malum in se abachler's Avatar
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    Quote Originally Posted by Elysia View Post
    I don't think you can "load" an exe, can you?
    You CAN load it using LoadLibrary(), but MS recommends against executing code in the module, this functionality is provided only so you can access resources in the executable.
    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.

  7. #7
    C++まいる!Cをこわせ! Elysia's Avatar
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    Hold crap, that code is messed up. Do you ever try to view your message before or after posting it?
    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.

  8. #8
    Malum in se abachler's Avatar
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    yeah i deleted it as soon as I saw what it looked like, sorry. Suffice it to say there is a tutorial in the MSVC 6.0 help file on creating a modeless dialog box.
    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.

  9. #9
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    I think there are at least three different solutions that are more appealing than "using a function out of another .exe":
    1. Share the source-code instead of the binary - so if "foo.c" contains your code, both project A and project B would contain a copy of "foo.c" - with the right type of source control, it should even be possible to make the source control understand that it's actually exactly the SAME FILE, just copied to two different places.

    2. Create a static library for "foo.c". Link both A and B to the foo.lib file.

    3. Create a proper DLL for foo.c, and link against foo.lib and distribute foo.dll.

    I understand that if A is an already existing application, you may not be able to use option 3, but option 1 and 2 doesn't actually change A in any externally visible way, so it should be fine.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  10. #10
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    Ok I see.
    It was just an experimental thing to me. I would had never used this in a productive environment due to the cleaner solutions matsp mentioned.

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