Building MSVC6 compatible DLL's with Newer Visual Studio - visual-studio

I'm about to begin a project for building a plugin to a large simulation system built with MSVC6, and offering instructions for compiling DLL's using MSVC6.
I have MSVC10 and 2012 available, and I'm wondering if it's even possible to configure these to build "down" to MSVC6 compatibility. Seems last time I dug into this, the answer was a resounding "No". Do I have to find an old MSVC6 install?
Update: There's also a 64-bit Visual Studio 2008 version of this that I could develop against, so same question: Can I configure a "new" visual studio (like 2012 or so) to compile down to VC6 or 2008 compatibility?

You can take an alternative approach, if you create your new project as a COM dll you can interact with it from MSVC6 however you will need to deliver any new linked runtime dlls as well in your resulting setup.

Related

Ye Olde VB6 project: how to recover it?

I have to debug an old VB6 project, and I can't manage to open the .vbp file with Visual Studio (even with the help found in some topics)...
My question is simple: how can I do that nowadays?
I'm using VS 2010
You will need to use Visual Studio 2008 to upgrade the VB6 project, and then you can open the upgraded project with 2010.
Be aware that the VB6 project needs to be in a compileable state, and that even so the new project will probably not compile once you are done.
Also be aware that there will likely be some limitations on even a successful upgrade -- ie it almost certainly won't compile for 64 bit systems.

How to deploy a Win32 API application as an executable

How can I deploy my Win32 application as an EXE application so that others (who don't have VC++ installed) can use it?
I am using VC++ 2010 on Windows 7.
If you switch to "Release" mode when you compile your finished program (rather than "Debug", which you use for debugging it during development), you should get an executable that will run on a computer without Visual Studio installed.
However, that executable will still require the appropriate version of the C runtime library to be installed. For example, if you developed it in Visual C++ 2010, you will need version 10 of the CRT installed. This is a freely redistributable library, downloadable here.
So, you have several options for deployment:
Manual Deployment
Give people the bare executable file, and include the installer for the redistributable in another folder on the installation media. If they copy the executable to disk and cannot run it because they get an error message, they should install the CRT libraries from the included redistributable installer. Then the executable will run just fine.
This works great if you have relatively a computer-savvy audience, or you're deploying to a fixed range of machines (like across a school or corporation). But it doesn't work so well for general deployment to customers.
In fact, you don't even need the installer. You can just place the CRT DLLs in the same folder as your executable and it will run just fine. This is how I test apps I'm developing on clean VMs. It works like a charm. There's no need to run the CRT installer at all. You'll find these required libraries as part of your Visual Studio installation:
<Program Files folder>\Microsoft Visual Studio 10.0\VC\redist\x86
Automated Deployment
Create a setup program that automatically installs your application along with any dependencies it requires, including the CRT redistributable. This is what you see most commercial applications doing. I recommend it for anything but the most trivial of apps.
Full versions of Visual Studio 2010 (i.e., not Express versions) can create a Setup Project that you can customize as needed to work as an installer for your application. But this is no longer the recommended way to create an installer, and this functionality has been removed from the latest version of Visual Studio, 2012.
So I recommend using something else, even if you have an older version of VS where the Setup Project is available. No point in wasting time creating something you'll just have to update later. My personal favorite choices for creating setup programs are WiX and Inno Setup. Both are free, and extensive documentation is available online.
Creating simple setups that don't have to do very much is really quite straightforward—this is likely the case for you, as all you need to do is install the CRT redistributable if it is not already there. I'd be willing to bet money you can find a walkthrough or example online for how to do this in either WiX or Inno Setup.
If you need to do more complicated stuff, both of these setup packages support it. They are extensively customizable and very powerful, it just takes more work to get it all going.
Static Linking
If you absolutely need to be able to distribute a bare executable that is guaranteed to simply work when double-clicked, you will need to switch your project to statically link in the required runtime libraries. This means that all of the CRT code is actually embedded by the linker directly into your executable, and means that you don't have to redistribute the CRT libraries separately.
The disadvantage of this approach is that the only way to benefit from improvements, bug fixes, and security patches released for the CRT is to recompile and redistribute your application. If you dynamically link (the default), your app will automatically benefit from enhancements to the installed version of the CRT libraries. Microsoft strongly recommends against static linking.
To switch between these modes in Visual Studio, follow these steps:
Right-click on your project in the Solution Explorer and select "Properties".
Ensure that the "Release" configuration is selected in the drop-down box at the top of the dialog.
Expand the "C/C++" item in the TreeView, and select "Code Generation".
Change the setting of the "Runtime Library" option to "Multi-threaded (/MT)".
A further description on what these cryptic compiler switches mean and which ones you should use when is given in my answer here.
Final Note: The "Debug" versions of the CRT libraries are not redistributable, but that doesn't matter because you should always distribute the "Release" build of your app anyway, never the "Debug" build.
In general, the odds are pretty good your EXE file will run on any version of Windows you built it on or higher.
All bets off, for example, if you built using Visual Studio 2012 Professional on Windows 7, and you try to run it on Windows 95. But otherwise, you're probably safe :)
The best way to test if you have any dependencies is to install and run on a "clean machine".
The best way to get (and reuse) a "clean machine" is with a VM.
I recommend VMWare. But Virtual Box and Windows Virtual PC are also viable choices.
As far as an installer, I'd strongly encourage you to look at InnoSetup
I hope that helps!
Make sure you build in release mode. As Floris Velleman said, you're using unneeded libraries for standalone executable.
For more information, you can check Compiler Options (MSDN).

Lowering a Visual C++ 2010 framework target

I've browsed around StackOverflow but couldn't find any pratical solution to something that would seem to have such an easy solution: I had a bunch of .Net projects that were developed back in VS2005 or VS2008 and I imported them into VS2010. One of them is a C++ project, which currently targets framework 4.0 (not by my choice). One of our clients is having a problem running this application, the lack of a MSVCP100D.dll. I checked this thread what is MSVCP100D.dll? and the most accepted answer is simple: having the client install Microsoft Visual C++ 2010 Redistributable Package. However, the client is stubborn enough not to install it and I know for a fact that they have Microsoft Visual C++ 2008 Redistributable installed. So, if I'm correct in my conclusions and MSVCP100D.dll is new to VS2010, I could just target a previous framework version, rebuild the project in VS2010 and I'd be good to go. The problem is: how do I chance a VC++ target framework? I could find several guidelines to change C# and VB projects, but none about VC++. Any pointers?
Edit: To you guys who suggested that I compile it in Release mode: I am! It's been pointed out that the "D" stands for debug, which is rather strange.
Actually, you are using the debug version of the runtime (That's the "D"). Did you try compiling with a non-debug version?
Another possibility to consider would be to statically link with the runtime library. Your program will be larger, but will not have the DLL dependency.
Go into the project's properties.
On the lefthand side, go into Configuration Properties > General.
Look at the Platform Toolset value. Select v90 from the drop down list to target 2008.
See here for further details:
Visual C++ 2010 compatibility with VC 2008
See here for yet even more details:
http://blogs.msdn.com/b/vcblog/archive/2009/12/08/c-native-multi-targeting.aspx
Also as Dark Falcon mentions, that's the debug version of the runtime.

Include c++ as pre-req, but says "A new version already exists"

I'm using the Visual Studio Setup project. If I go to the properties of the Setup project, it lets me choose which pre-reqs are required, at which point I choose the C++ Redistributable.
On some systems, this works fine - but recently my users are reporting that the install failed because "A newer version of Microsoft Visual C++ 2010 Redistributable has been detected on the machine."
What's the proper way to do this? Is Visual Studio's detection fouled up somehow and unable to detect C++?
Yuck, this is ugly. I was wondering what would happen after Microsoft gave up on the side-by-side install of the runtime DLLs for VS2010. Seems clear, the interwebs are full of this installer error. The biggest victim seems to be Microsoft itself with Streets and Maps failing to install.
I'm not aware of any security patches for it so I have to guess that you haven't updated to SP1 yet. And your customers use a product of a vendor that did. This is a battle that you're always going to lose some day. Do consider taking advantage of the app-local deployment for the DLLs, copying them in the same directory as your main EXE. Simply copy them from the vc/redist directory before putting the setup package together, no need to tick the prerequisite. You'll need:
msvcr100.dll and msvcp100.dll for the regular CRT
atl100.dll if you use ATL
mfc100.dll, mfc100u.dll, mfcm100.dll, mfc100u.dll if you use MFC (u = Unicode, m = managed)
mfc100xxx.dll where xxx is the 3 letter language code if you use MFC on a non-English machine
vcomp100.dll if you use OpenMP in your code.
Only disadvantage is that they won't get updated if there's a security patch. That could be an advantage too, depending on what color glasses you wear. If you're uncomfortable about it then keeping the machine that creates the setup package updated, including enabling Windows Update, is an important requirement.
The default Visual C++ 2010 Redistributable uses a Product Code for detection. So Visual C++ 2010 SP1 Redistributable is not detected as installed. This is why the package tries to install it and fails.
A good solution is to create your own custom prerequisite which uses a better detection criteria. Here is an article which may help you:
http://blogs.msdn.com/b/astebner/archive/2010/05/05/10008146.aspx
Visual Studio setup projects do not support custom prerequisite creation. However, it can be done by manually generating the required manifests.
You can find the manifests structure here: http://msdn.microsoft.com/en-us/library/ms229223(VS.80).aspx
These manifests can be generated automatically with the Bootstrapper Manifest Generator tool.
After generating the package manifests, you can add all these files (including the package) in a separate folder in the Visual Studio prerequisites folder, for example:
C:\Program Files\Microsoft SDKs\Windows\v7.0A\Bootstrapper\Packages\
This way Visual Studio will show the prerequisite in your setup project properties page.

Visual C++ 2010: Changes to MSVC runtime deployment (no more SxS with manifest)

Where can I find some official note, kb article or other documentation describing changes to the Visual Studio 2010 C/C++ runtime linking and deployment policy?
Under Visual Studio 2008 (with the VC90 runtime) a manifest was embedded in native images, and the runtime libraries were deployed as side-by-side assemblies (WinSxS). This caused problems when rebuilding a native exe or library using VS 2008 SP1, in that an updated version of the C++ runtime was required by the embedded manifest.
For VS 2010 and the MSVCR100 runtime version, the policy seems to have changed completely.
The file msvcr100.dll and the other C/C++ runtime libraries are no longer install as SxS assemblies.
When compiling under VS2010, no runtime 'dependency' entry is added to the embedded manifest, meaning that any version of msvcr100.dll might be loaded at runtime.
On machines with .NET 4 installed, the matching runtime is named msvcr100_clr0400.dll, and won't be loaded by native code, though a copy renamed to msvcr100.dll works fine. I think this means any process with C/C++ code will always have two versions of the same C/C++ runtime loaded.
This seems to be a significant change in policy, backtracking from the SxS deployment and manifest dependencies we had under VS 2008. Could anyone shed more light on what changed, and perhaps point to some documentation, a readme or blog post that describes these changes, the motivation and related impact?
It think it's better this way - the strong version manifest and SxS deployment was a nightmare - but I'm surprised at these unexpected and seemingly undocumented changes in VS 2010.
Bonus question: How can I compile my C++/CLI library under VS 2010 to link to msvcr100_clr0400.dll instead of msvcr100.dll? This idea is that the C++/CLI assembly should run with no dependencies other than that installed by .NET 4 (without static linking).
You already answered most of your question, the side-by-side deployment of the CRT was a nightmare that got way too many programmers in trouble. Microsoft agreed and gave up on it for the VS2010 release. It's back to a DLL in c:\windows\system32, named msvcr100.dll. And msvcp100.dll, vcomp100.dll, atl100.dll, mfc100.dll, mfcm100.dll, the other runtime support DLLs. The way it was for VS2003 and earlier editions. Now it is again the user's burden to sort out a DLL Hell problem. The person least likely to be able to do so but they do tend to have a budget to pay for support. Unlike programmers that need to get help from a free web site :)
But you can help, app-local deployment is now again enabled, you can deploy msvcr100.dll in the same directory as your main EXE. That was explicitly checked and forbidden in previous versions. App-local has some niceties, it isolates you from well-meant but unfortunate updates that break your app. Albeit that you are now yourself responsible for getting updates deployed that fix a security hole. If that's uncomfortable then deploy and rely on the copy in the system directory.
Do not try to link to msvr100_clr0400.dll, that's a private copy for use by the CLR. Much like msvcr.dll is a private copy for use by Microsoft DLLs. You don't have the .lib file you need to link to these DLLs.
Just a couple of links about the topic – I hope someone will find them useful:
Visual Studio 2010 changes for VC++ (part 5)
Visual C++ Application: How to use manifests and re-distributable assemblies?

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