问题
I inherited a substantial amount of code, including a visual studio project that is supposed to (as best as I can tell) build a .lib file. Visual studio says "... Generating Code... Creating Library... Creating browse information file...", and at the end, it says the build succeeded. In the release/debug folder, it has a bunch of .obj files, but it doesn't have a .lib file. What could I be missing?
Thanks!
回答1:
Open the Project Properties (right-click the project in Solution Explorer, select 'Properties'). Under 'Librarian', check 'Output File' - that's where the output should go.
If this looks right, try dir /s *.lib in a suitable subdirectory for your project, to see if you can locate the output library by date and time. If you still can't find it, try a clean rebuild (right click project, select 'Rebuild').
For DLLs, a .Lib file is not created if the DLL exports nothing for external usage. I don't think this applies for static lib builds but I would make sure you are exporting something public from your library project source code.
回答2:
.lib will not get generated if you miss to add prefix __declspec(dllexport) for methods.
回答3:
My static library contains nothing but two template classes, so I didn't have a .cpp file. This caused Visual Studio 2015 to not output a .lib file. To solve this, I made a file huh.cpp which includes all of the headers.
回答4:
I had the same problem, even though I was already using the __declspec(dllexport) function.
Your ProjectName.cpp file needs to #include "ProjectName.h". If you don't include the header file then the functions don't get exported. The DLL builds fine, no errors or warnings (at least in VS2017 15.8), but you don't get a LIB file.
Include the header and boom - LIB file is generated. A rookie mistake I'm sure, but everyone has to start learning somewhere.
回答5:
I just ran across this problem as well.
It was due to using an invalid macro in the output directory definition. In my case, it was
when it should have been
I had to blank out the full path in the second screen shot. I had an incorrect macro. I was using MsBuildProjectDir when I should have been using MsBuildProjectDirectory. The read-only text box will show the full path (eg: C:\Development\blah\blah\blah\) when the output directory is valid. If the output directory is not valid, you'll get something like the first screenshot.
回答6:
If the Methods you want to export are in a class, you have to __declspec(dllexport) on the class. Otherwise no .lib will be created.
回答7:
I was exporting a class from the dll but had declared the class inline in .h file. The .cpp file was there but empty. This setup was causing the .lib file to be not generated.
I moved the implementation of functions to .cpp file and now lib file is generated.
This is in VS2019.
回答8:
In the DLL project, put __declspec(dllexport) beginnings of methods defined in .h and .cpp files.
After all, compile your dll again, so .lib file will be generated and ready for linking.
put Class Foo
{
public:
__declspec(dllexport) int GetFoo() const;
回答9:
Had the same issue here with VS2019. In my case I had built a few times with no symbols defined (i.e. cpp files were empty).
After I added symbol definitions into the cpp files I began to notice this issue (no lib file was being generated).
A simple clean via 'Rebuild all' fixed it. Perhaps if you build whilst there are no symbols defined, something gets cached somewhere that you have an empty product DLL, and you need to clean the solution to reset that cached state.
回答10:
My issue was that in the projects Properties>C/C++>CommandLine, I had specfied the switch incorrectly.
That is instead of writting /D_HASHING_BUILD_DLL I had written /D_Hashing_BUILD_DLL.
Side note:
This is how I build my DLL/Lib files in Visual studio : (and my Hashing.h looks like this: )
#ifndef HASHING_H
#define HASHING_H
/* If we are we on Windows, we want a single define for it.*/
#if !defined(_WIN32) && (defined(__WIN32__) || defined(WIN32) || defined(__MINGW32__))
#define _WIN32
#endif /* _WIN32 */
#if defined(_WIN32) && defined(_HASHING_BUILD_DLL)
/* We are building Hashing as a Win32 DLL */
#define HASHING_API __declspec(dllexport)
#elif defined(_WIN32) && defined(HASHING_DLL)
/* We are calling Hashing as a Win32 DLL */
#define HASHING_API __declspec(dllimport)
#elif defined(__GNUC__) && defined(_HASHING_BUILD_DLL)
/* We are building Hashing as a shared / dynamic library */
#define HASHING_API __attribute__((visibility("default")))
#else
/* We are building or calling HASHING as a static library */
#define HASHING_API
#endif
//your inlcudes
class HASHING_API MyClass
{
//...
};
#endif // !HASHING_H
and in the path I stated earlier, I just use the switch I defined here and there you go, the DLL is built just fine!
来源：https://stackoverflow.com/questions/3950509/build-succeeded-but-no-lib-file-gets-created