Visual Studio 2010 MSVCR dependency removal?

问题:

I've tried Googleing this but I could not find a solution. I am trying to learn some basic C++. I wrote a simple hello world:

#include <stdio.h>
int main()
{
    printf("hello, world\n");
    return 0;
}

It compiled perfectly and everything! Great I thought, so I loaded up my virtual machine with XP and no service packs installed, then tried to run it. It told me I needed the MSVCR dll. Is there any way I can completely remove this dependency? I don't want to stuff the program with the dll. I want it to be gone, completely. Is it possible to make and run a program that will run in XP and up? Thanks.

回答1:

It is technically possible to remove this dependency in C, but I'm not sure it is even possible in C++. And in either case, I would not recommend it. You lose a lot of stuff that the CRT does for you behind the scenes, most of which you don't want to have to reinvent yourself in an inferior fashion. For starters, it's the runtime library that actually calls your main function as well as calling the constructors and destructors for global and static C++ objects.

The best and simplest solution is probably to change how your application links to the runtime libraries. You have two different options: dynamically and statically. Dynamic linking is more memory-efficient and means that your application will take advantage of any bug fixes that are made to the library. It relies on the runtime DLL being present in order for your app to start. Static linking actually embeds the runtime library code into your application during the link phase of the build. This means that you can run without distributing the DLL, but there are important caveats.

For simple apps, it's unlikely that these caveats are relevant. Change the link style in use in your project's options:

1. Right-click on your project name in the Solution Explorer.
2. Expand the "C/C++" option in the left-hand treeview, and select the "Code Generation" item.

3. In the "Runtime Library" property combobox, choose one of the "Multi-threaded" options.
   Debug builds should use "Multi-threaded Debug", while Release builds should use "Multi-threaded".

   

Do note that since you're using VS 2010, you can still choose to dynamically link to the runtime and gain all of the advantages of doing so without having to run the CRT installer on the target machines. All you need is the redistributable DLL(s) placed into the same folder as your application's executable. This makes deploying (and even testing) very simple and straightforward. You'll find these libraries as part of your Visual Studio installation:

\Program Files\Visual Studio x.0\VC\redist\

And of course, the debug versions of the CRT are never redistributable. Since you should not distribute debug versions of your application, this is not a problem. Make sure that you've compiled a "Release" build (using the drop-down combobox in the top toolbar), for which you will require only the redistributable libraries found in the above directory.

---

Can't I use the runtime that comes with XP?

There is no C runtime for you to use that comes with any version of Windows. Windows itself indeed depends on a C runtime library, but it deploys a private version of that library for its own use. Applications are not intended to link to it or make use of it in any way. You're on your own for deploying all necessary dependencies, and as you've noticed, you cannot assume that the target machines will already have the correct version(s) installed.

回答2:

You can link the MS runtime statically, Project Options -> C/C++ -> Code Generation -> Multithreaded (or Multithreaded Debug for debugging configuration). No DLL should be needed then.

回答3:

you can remove the annoying run-time library, do this:
project properties > linker > input > ignore all default libraries> yes

this will give you quiet a few issues you need to deal with, for example, floating point numbers won't work, stack memory is very small (about 3k), there's no built in help against buffer overflows and such, and you can't use the standard library without copy pasting it in your project.

this will also decrease the size of the .exe nearly equivalent to as if it was hand made in assembly.