CODEWITHSUNDEEP
c#.netdll
Krimson
Krimson

Reputation: 7664

What is a .exp file and .lib file, and how can I use them in my C# project?

I wanted to download the lame library for use in my C# project to convert audio. I found the files to use here (libmp3lame)

When I downloaded the archive, I found the .dll I was looking for but along with them, there were 2 others files:

My question:

  1. 1 What are these files used for? And how can I make use of them in my project apart from the .dll file
  2. What benefit do these files give me that the .dll library cant?

Edit: I have a feeling that these files are not for use in C#. More for C++. But either way, what are those files? And what are they used for?

Upvotes: 6

Views: 3947

Answers (2)

Ben Voigt
Ben Voigt

Reputation: 283684

If you think about the method for consuming a native DLL in .NET (p/invoke), your p/invoke declarations have several parts:

  • The function signature (return time, argument types)
  • DllImportAttribute specifying the DLL where the function is found and its key in the export table (mangled name or ordinal)

In C and C++, the header file provides the first, and the import library, ending in .lib, provides the second.

Unlike p/invoke's DllImportAttribute, in C and C++ the calling convention is stored with the function signature in the header file.

Upvotes: 0

Icemanind
Icemanind

Reputation: 48696

Both lib files and exp files are used with native code development (e.g. C++/VB6/Win32) and are not used at all in the .NET world.

lib files contain a collection of reusable code or data or both that can be statically linked and reused with your existing code. They are similar to DLL files, except the big difference being DLL files are linked dynamically and LIB files are linked statically, when you compile your program.

exp files are export files. There are kind of like metadata files that tell your compiler which functions in a DLL have been exported, and therefore can be reused in your statically linked program. .NET program do not require this because each .NET DLL has a special section called the CLR Metadata section. .NET programs can use reflection to pull this metadata information and see which methods are available.

Upvotes: 6

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