Cannot link to proper libraries on Windows 11 Pro.

[huskier]

We want to use libvips to read and write images in our Qt application on Windows 11 Pro with MSVC2019 toolkit (x64). We've downloaded vips-dev-8.15.

We've dealed the include headers, and the application have passed compilation.

For the linker, we have told the linker to link the vips libraries:
LIBS += -LD:/development/github_gitlib/vips-dev-8.15/lib -llibvips-cpp -llibvips

However, we still got "unresolved external symbos" errors as the following output.

"__declspec(dllimport) public: class vips::VOption * __cdecl vips::VOption::set(char const *,int)"
"__declspec(dllimport) public: static class vips::VOption * __cdecl vips::VImage::option(void)"
"__declspec(dllimport) public: static class vips::VImage __cdecl vips::VImage::new_from_file
"__declspec(dllimport) public: __cdecl vips::VImage::~VImage(void)"

Are there any needed libraries we forgot to link?

The code snippet in our source is as following:

    VImage in = VImage::new_from_file ("D:/development/DCS/tests/pcb.png", VImage::option ()->set ("access", VIPS_ACCESS_SEQUENTIAL));
    vips_shutdown ();

[jcupitt]

Hello @huskier,

The C++ binary we provide for windows is for gcc 15. C++ has no ABI, so you have to match the compiler and compiler version exactly along your whole toolchain.

If you are using MSVC, you will need to rebuild the libvips C++ binding yourself. It's very easy -- just copy these files into your project:

https://github.com/libvips/libvips/tree/master/cplusplus

[huskier]

Thank you for your reply, @jcupitt.

My understanding is that we do not need to link the libvips-cpp.lib, if we have all the cpp source code embedded into our project. However, after copying those cpp files into our project, we've gotten more "unresolved external symbos" errors (78 more).

Something I forget?

We've confirmed that the following C API interface could be compiled, linked and run without problem.

VipsImage *in;
in = vips_image_new_from_file("D:/development/DCS/tests/pcb.png", NULL);

[huskier]

We've gotten the solution.

1. #define VIPS_CPLUSPLUS_EXPORTS
2. Appending "-llibglib-2.0 -llibgobject-2.0" to the following line.
   LIBS += -LD:/development/github_gitlib/vips-dev-8.15/lib -llibvips -llibglib-2.0 -llibgobject-2.0
   Finally, the errors have gone!

Now, we could happily use VIPS, and we like it very very much!

[jcupitt]

I'm glad it's working! Thanks for the update.