Say,if the .dll or .lib is written in C,can it be used by other languages like PHP/Python?
A DLL is binary. As long as your language can consume a binary library (with the OS the binary was compiled for), you should be okay (see exceptions below). LIB files are for the compiler so you'll only be able to use those by C/C++ languages at compile time.
The exception to this is .NET and COM. .NET generates special assembly DLLs to be used by other .NET languages (C#, VB.NET, C++/CLI, IronPython, etc). COM generates special DLLs as well where components (specialized classes) are exposed through the DLL. Natively, C++ and VB6 support COM. .NET languages can access COM DLLs through an interop. Many other languages also support COM bindings by various means.
Go here for a discussion on this topic and more details about the differences.
Related
Since the command-line tools x86_64-w64-mingw32-widl on Linux and widl on Windows both are able to produce type libraries, the .tlb files, for COM clients to import, it's reasonable to surmise that it might be doable to use MinGW toolset to build a COM client that is able to acquire COM interfaces by using smart pointers offered by the .tlb file, instead of calling function CoCreateInstance to get the interfaces. The question is how?
Visual C++ has its nonstandard directive #import to introduce the smart pointer types (and other stuff) to C++ code. What is the counterpart when we are using MinGW g++?
By the way, I've been googling all day and found it difficult to find useful information about "MinGW + COM". Most of them use Visual C++. If you know somewhere out there a good online tutorial on this topic is, please let me know. Thanks.
A legacy VB6 app I maintain has dependencies on some third-party DLLs. DLL information (from embedded metadata) is pasted below.
I am looking for any pointers to documentation, a current vendor who supports these DLLs, or any tribal knowledge at all about what they do.
I have a piece of code that compiles for both the Silverlight and the .NET targets. It depends on Json.NET and SharpZipLib. My goal is to make a portable library that Silverlight and .NET projects can both link against.
Since there is no version of SharpZipLib targeting "portable-net40+sl50", I have a problem.
However, if I knew how, I would be willing to write the wrapper code myself.
So: How can I write a portable library that depends on Silverlight's SharpZipLib when being linked against from Silverlight and depends on .NET's SharpZipLib when being linked against from .NET?
Is that at all possible or is that something only Microsoft can do?
If your code uses a limited sub-set of the SharpZipLib API, you could create a "dummy" PCL library comprising this API subset, but without any functionality implemented.
What you then must do is to change the strong name (assembly name and signing) and version of the existing .NET and Silverlight SharpZipLib:s to be the same as your "dummy" PCL SharpZipLib and re-compile the platform specific libraries as well.
With this set of assemblies (PCL, .NET and Silverlight) you will now be able to consume the PCL library from other PCL libraries. In a platform specific application that makes use of PCL libraries that in turn consumes the SharpZipLib library, you should explicitly reference the platform specific SharpZipLib library that has the same strong name and version as the PCL analogue.
You should find more about this technique ("bait-and-switch") here and here. The PCL Storage project is also a good example of where this technique has been applied.
System.Data.SQLite (SDS) is apparently the most popular way to use SQLite from a .Net application.
I was wondering if
SDS requires shipping the SQLite DLL in addition, or if SDS includes
the SQLite source code, and
SDS can be statically compiled into a
VB.Net application of it can only be shipped as a DLL?
Thank you.
To expand on my comment, SDS is a .net wrapper for unmanaged code, so you will need to ship your release code with a copy of the DLL.
As Steve mentions, there are 32 and 64bit versions of the DLL, and as i discovered after much frustration, you must have the corresponding visual c++ runtime installed on the target machine, so if you deploy the 32bit version onto a 64bit machine, it will need the 32bit c++ runtime environment installed.
An alternative that i am currently looking into but havent had time to test is csharpe-sqlite, a pure .net implementation:
http://code.google.com/p/csharp-sqlite/
Coded in c# as the name suggests, but of course usable in any .net language including vb.net
Actually it's quite easy to compile System.Data.SQLite.dll to the does not require C++ runtime. For example if you download source code and follow the build procedures you'll find statically linked (no C/C++ runtime required) copy of System.Data.SQLite.dll in the following path:
<your-src-root>\bin\<2008 or 2010>\<Win32 or x64>\ReleaseStatic
For example if your source is in C:\Work\sqlite-netFx-source-1.0.80.0 then statically linked binary for Win32 and .NET 3.5 (VS 2008) will be located in:
C:\Work\sqlite-netFx-source-1.0.80.0\bin\2008\Win32\ReleaseStatic
Furthermore since System.Data.SQLite.dll is a mixed-mode assembly consisting of a managed .netmodule and native .obj file linked together using link.exe, it is possible to build your app as a .netmodule as well and link it together with SQLite into a single mixed mode assembly.
The resulting assembly will still be either Win32 or x64, however since almost all x64 machines will have no problem running Win32 code you can just settle on Win32 as long as:
Your app is an .exe or a .dll the is always loaded into a Win32 process, and
You don't use any of x64 specific advantages such as larger address space or using unmanaged code available only in x64
I am a .net developer who has never touched c++. I don't want to either :)
Unfortunately, I have to work with c++ module in .net 4.0 and I am clueless.
Is there a tool that can generate a .net assembly for a given c++ module?
If not, what are my next steps to successfully call these c++ libraries?
There are many ways:
COM Interop
Tlbimp.exe (Type Library Importer)
How to: Generate Primary Interop Assemblies Using Tlbimp.exe
The Type Library Importer converts the type definitions found within a COM type library into equivalent definitions in a common language runtime assembly.
PInvoke/DllImport
Calling Native Functions from Managed Code
The common language runtime provides Platform Invocation Services, or PInvoke, that enables managed code to call C-style functions in native dynamic-linked libraries (DLLs). The same data marshaling is used as for COM interoperability with the runtime and for the "It Just Works," or IJW, mechanism.
C++/CLI
Mixed (Native and Managed) Assemblies
How To: Migrate to /clr
This is more advanced because it will most probably require the C++ module to be updated and re-compiled.
Mixed assemblies are capable of containing both unmanaged machine instructions and MSIL instructions. This allows them to call and be called by .NET components, while retaining compatibility with components that are entirely unmanaged. Using mixed assemblies, developers can author applications using a mixture of managed and unmanaged functionality. This makes mixed assemblies ideal for migrating existing Visual C++ applications to the .NET Platform.