I'm building a dll on Visual Studio 2010, and I'm using some simple C functions like fprintf and fread, and it's linking to msvcr100.dll by default.
This dll is going to be loaded into an app that may be using a different CRT version (eg. msvcr90.dll, msvcrt.dll).
Since I know the app's going to load a CRT before my dll gets loaded, can I remove the dependency on msvcr100.dll and use the C functions in the CRT loaded by the app?
In the end, I decided to build the DLL against the lowest common denominator CRT version used by the target app, msvcr90.dll.
I did this by using the MSVC toolchain, available with Visual C++ 2008 Express (free).
I did try the mingw/gcc toolchain, which allows you to specify which CRT version to link against (see mingw-rt and gcc -specs=msvcr**), however, msvcr90.dll is a new-style SxS assembly so I couldn't get the produced executable to run properly.
It may be worth considering skipping linking against msvcr**.dll entirely; see this post and VC/include/delayhlp.cpp.
Related
After reinstalling Visual Studio 2010, I recompiled the code and encountered the following error:
Error 'LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt'
A solution mentioned that the lib file is incompatible and I need to install Visual Studio 2010 SP1. I did that, and now it has been solved.
I am wondering how can I check whether a lib file is created by SP1 or not?
I tried dumpbin, but I cannot find the version in its result.
It was not an incompatibility with your LIB file that caused the problem here, so checking the version of the linker that created it would not be a solution anyway.
The issue is that cvtres.exe (used internally by the linker toolchain) depends on a particular DLL (msvcr100_clr0400.dll) shipped with VS 2010 RTM. When you update to a later version of the .NET Framework (e.g., by installing .NET 4.5 or installing a later version of VS), this DLL is replaced. That stops cvtres.exe from working.
The reason why installing VS 2010 SP1 fixes it is because it actually modifies the cvtres.exe application to break the dependency. And now that all pieces of the linker toolchain work, you can compile and link the code without error.
Of course, there are other problems you can have when you start mixing libraries created by different versions of the compiler and/or linker. They aren't guaranteed to create 100% compatible output, so mixing them is not supported (at least not between major versions, I'm uncertain about how this rule applies to service packs).
In general, it's best to just recompile all libraries whenever you update your build system. The only time you wouldn't do this is if you didn't have the source code, in which case, you need to be very careful about updating your build system, lest you introduce gratuitous incompatibilities.
As far as determining the version of the linker that prepared a particular binary, using dumpbin.exe (included with the SDK) is exactly the correct approach. For static libraries, run the following command from the Visual Studio SDK Command Prompt:
dumpbin /rawdata:1 MyLibrary.lib
You'll see the assembly manifest, which will include the full path to the compiler used to build the library as well as the version of the CRT that it depends upon.
For dynamic libraries (i.e., DLLs) and executables, run the following command:
dumpbin /headers MyApp.exe
Look under the "Optional Header Values" section (not actually optional) for the version of the linker, along with a timestamp of when it was generated.
Note that you're very unlikely to find this information in release builds of a library or binary.
I'm writing a simple C++ application in Visual Studio. It also has a setup project.
It works well on my development machine, but when I'm installing this application on user's machine it requires Visual C++ Redistributable Package. I'm wondering why does my application require C++ Redistributable? Standard C++ runtime library is shipped with Windows, isn't it?
The only version of the C runtime library which is shipped by Microsoft with most of 32 bit Windows versions is msvcrt.dll. This library provides a typical set of library functions required by C and C++ programs. These include string manipulation, memory allocation, C-style input/output calls, etc.
Visual Studio 6.0's compiler links against this library, so if you are developing in VS 6.0 you shouldn't encounter any problems on most users' machines.
However, if you are developing in VS 2005, VS 2008, VS 2010, VS 2012, VS 2013 or VS 2015, you have to distribute additional C runtime libraries along with your application. This is because their compilers link against msvcrt80.dll, msvcrt90.dll, msvcrt100.dll, msvcrt110.dll, msvcrt120.dll and msvcrt140.dll respectively, which are not shipped with Windows.
Solutions:
Possible solution is to link statically with runtime library, but it may cause a lot of problems in case you have both .exe and .dll in your application. Don't do that.
To be more specific, I'll allow myself to quote a part of this answer:
Using /MT is risky if you create DLLs as well as an EXE. You'll end up
with multiple copies of the CRT in your program. This was especially a
problem with earlier versions of VS where each CRT would get its own
heap, not so much with VS2012. But you can still have ugly runtime
problems when you have more than one "errno" variable for example.
Using /MD is highly recommended to avoid such lossage.
Another possible solution is to require an appropriate Microsoft Visual C++ Redistributable package to be installed on the user's machine.
It may be done by specifying this requirement in prerequisites property in your setup project.
Also, you can distribute the runtime dll by including in your setup project the appropriate "merge module". In this case don't forget to add the appropriate "policy merge module" to avoid errors caused by incorrect runtime version.
Finally, you can just put required DLLs in the same folder in which your application is installed.
Further reading:
"Redistributing Visual C++ Files" - Official MSDN documentation
Even though some comments said that «link statically with runtime library, but it may cause a lot of problems when you have both .exe and .dll in your application.» this is NOT TRUE. First we DON'T statically link DLLs! We statically link OBJs and LIBs. LIBs are static libraries; DLLs are dynamic libraries, and you may choose to use LIBs (static) or DLLs (dynamic). It's entirely up to you to choose. The ONLY drawback (for the DLL fans) is that if you want to update one library, you need to compile and link again. I personally deploy ALL my software static linked and because of that I earn the bonus of don't even need installers. The software I develop is 100% portable (a feature that in the pre-installer era was general procedure), and the final user is free to simple COPY from one folder to another or even from the hard drive to flash drive (or vice-versa). The error message «DLL not found.» simply doesn't exist ... NEVER.
Some folks think of statically linking as toy software: WRONG! I can write a full featured application that connects to a DBMS (Oracle, SQL Server, ...) or any other kind of application.
I know this has been asked in other places and answered, but I'm having issues with MS Visual Studio 2010. I've developed a C++ executable but if I run the Release version on a machine that doesn't have the VC++ runtime library (ie, msvcr100d.dll), I get the "program cannot start because msvcr100d.dll is missing from your computer" error.
This is weird for two reasons:
Why is it trying to link with the debug version of the redistributable?
I tried applying this fix, setting the runtime library setting to /MT instead of /MD (multi-threaded DLL), but that only made the problem worse (if I manually copied msvcr100d.dll, it then said it couldn't find msvcp110.dll).
How can I package the runtime library with my executable so that I can run it on machines that don't have MS VC 2010 or the redistributable installed?
I know it's considered a security risk to include a copy of the DLL since it won't ever be updated, but my goal is just to send this executable to a few friends in the short term.
You definitely should not need the debug version of the CRT if you're compiling in "release" mode. You can tell they're the debug versions of the DLLs because they end with a d.
More to the point, the debug version is not redistributable, so it's not as simple as "packaging" it with your executable, or zipping up those DLLs.
Check to be sure that you're compiling all components of your application in "release" mode, and that you're linking the correct version of the CRT and any other libraries you use (e.g., MFC, ATL, etc.).
You will, of course, require msvcr100.dll (note the absence of the d suffix) and some others if they are not already installed. Direct your friends to download the Visual C++ 2010 Redistributable (or x64), or include this with your application automatically by building an installer.
For me the problem appeared in this situation:
I installed VS2012 and did not need VS2010 anymore.
I wanted to get my computer clean and also removed the VS2010 runtime executables, thinking that no other program would use it.
Then I wanted to test my DLL by attaching it to a program (let's call it program X).
I got the same error message.
I thought that I did something wrong when compiling the DLL.
However, the real problem was that I attached the DLL to program X, and program X was compiled in VS2010 with debug info. That is why the error was thrown.
I recompiled program X in VS2012, and the error was gone.
This problem explained in MSDN Library and as I understand installing Microsoft's Redistributable Package can help.
But sometimes the following solution can be used (as developer's side solution):
In your Visual Studio, open Project properties -> Configuration properties -> C/C++ -> Code generation
and change option Runtime Library to /MT instead of /MD
Usually the application that misses the .dll indicates what version you need – if one does not work, simply download the Microsoft visual C++ 2010 x86 or x64
from this link:
For 32 bit OS:Here
For 64 bit OS:Here
I got the same error.
I was refering a VS2010 DLL in a VS2012 project.
Just recompiled the DLL on VS2012 and now everything is fine.
Debug version of the vc++ library dlls are NOT meant to be redistributed!
Debug versions of an application are not redistributable, and debug
versions of the Visual C++ library DLLs are not redistributable. You
may deploy debug versions of applications and Visual C++ DLLs only to
your other computers, for the sole purpose of debugging and testing
the applications on a computer that does not have Visual Studio
installed. For more information, see Redistributing Visual C++ Files.
I will provide the link as well : http://msdn.microsoft.com/en-us/library/aa985618.aspx
I have a C++ dll. Is there a way to compile it so that it can be used with VS2005/2008/2010 instead of me having to do 3 different builds?
Thanks
You can generally "use" a C++ dll with any version of Visual Studio, if you're just linking to it.
However, when your dll is compiled, it will be targetted to a specific version of the C++ runtime, so end-users of your program will need to have that runtime (Visual C++ redistributable package) installed on their PC. So if you use a dll built by VS2005 and an exe built by VS2010, your end user will have to install both the 2005 and 2010 redistributable packages. The same generally goes for other libraries if you use them (MFC, etc)
If you do this, you will also have to be careful about memory allocation - memory allocated in one runtime version cannot be safely deallocated by another. So anything that your dll allocates must also be deallocated by the dll, and anything allocated by your exe must not be deallocated by the dll.
As a result, most people will rebuild the dll with the same version of VS as they build the rest of their program in, to minimise the compatibility issues - ultimately it's much easier to build in each verison of VS than to sort out all the issues involved in not doing so.
(Hint: You can run VS from the command line and get it to build a project/solution, so it's a 5 minute job to write a batch script that will automate building all three variants in one go)
The version of visual studio in use doesn't make a difference as to whether a given assembly can be referenced.
The only thing that matters is what version of the framework the assembly was compiled against.. Assuming it's a .net assembly anyway.
Regardless, it's common practice to provide versions compiled against each framework rev (2.0, 3.5, and 4.0) anyway.
However, if you are compiling an unmanaged c++ dll; then just provide a 32 bit and a 64 bit version of that dll. In this case the .net version in use (and visual studio version for that matter) is immaterial.
I work on C/C++ using Visual Studio 2008. I believe that I am not concerned about which runtime libraries are being used by my code as I have the developer setup. But when the executable is shipped, the runtime libraries being used need to be shipped alongwith. Am I right?
If yes, how can I identify which shared libraries are actually getting used? Or are there any libraries that we can ship without having to know this?
You're correct, you need to ship a version of the C runtime libraries that matches the version you linked your application against. If you're compiling with Visual Studio 2008, then you want to use the Microsoft Visual C++ 2008 Redistributable Package. As other folks mentioned, you can inspect your application's manifest file to see exactly which version of the C runtime libraries it's linked against.
Before shipping, it's always best to install your product on a clean (i.e., non-developer) virtual machine and run Microsoft's Dependency Walker utility to verify that your application uses the correct C runtime libraries.
you need to ship dll files with you.
you can guess most of them and for the rest you can use a program "Dependency Walker" which shows you dependencies of the executable.
Look at the generated manifest file to see which version of the CRT you need to ship with. It's possible to change which version of the CRT you link to as seen here but it doesn't seem to be recommended.