Question

I m trying to link my project with fftw and so far, I ve gotten it to compile, but not link. As the site said, I generated all the .lib files (even though I m only using double precision), and copied them to C:Program FilesMicrosoft Visual Studio 9.0VClib, the .h file to C:Program FilesMicrosoft Visual Studio 9.0VCinclude and the .dll to C:windowssystem32.

I ve copied the tutorial program, and the exact error I am getting is:

1>hw10.obj : error LNK2019: unresolved external symbol __imp__fftw_free referenced in function "bool __cdecl test(void)" (?test@@YA_NXZ)
1>hw10.obj : error LNK2019: unresolved external symbol __imp__fftw_destroy_plan referenced in function "bool __cdecl test(void)" (?test@@YA_NXZ)
1>hw10.obj : error LNK2019: unresolved external symbol __imp__fftw_execute referenced in function "bool __cdecl test(void)" (?test@@YA_NXZ)
1>hw10.obj : error LNK2019: unresolved external symbol __imp__fftw_plan_dft_1d referenced in function "bool __cdecl test(void)" (?test@@YA_NXZ)
1>hw10.obj : error LNK2019: unresolved external symbol __imp__fftw_malloc referenced in function "bool __cdecl test(void)" (?test@@YA_NXZ)

So, what could be wrong with my project setup? Thanks!

Answer 1

Have you actually linked against the library in the project you re building?

Project -> Properties -> Linker -> Input -> Additional dependencies

You need to add the library s filename to that field.

Answer 2

My case

Using FFTW in Visual Studio 2010

Precompiled FFTW 3.3.1 Windows DLLs install using fftw-3.2.1-dll.zip, on my Windows XP machine.

Open cmd window and go to lib.exe folder C:Program FilesMicrosoft Visual Studio 10.0VCin>
Type lib /def:libfftw3-3.def
Type lib /def:libfftw3f-3.def
Type lib /def:libfftw3l-3.def
If you have a error on command, copy any mspdb80.dll or mspdb100.dll file to in bin directory.
You will get 6 files

libfftw3-3.exp, libfftw3-3.lib, libfftw3f-3.exp, libfftw3f-3.lib, libfftw3l-3.exp and libfftw3l-3.lib

and copy it to programming directory.
Delete all mspdb80.dll or mspdb100.dll file from bin directory.
Closed Project and open again and rebuild it again.

Answer 3

Assuming you ve actually linked your project against the lib and it doesn t work, use /verbose:lib and paste the output of that and the output of

dumpbin /exports fftw.lib | findstr fftw_free

Answer 4

I had similar problem. What helped was compiling the fftw libs with this help Compiling FFTW source in Visual studio. Actually more closely the problem was compiling my application Win 32 and trying to use x64 -libraries. So make sure the platform is same.

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