title: Mingw FFTW3 cannot find a library/header file
body: <p>I am on a Windows machine, and I am trying to get Mingw (with gcc/g++ 4.9.2) to recognize that I have a library installed.</p>
  
  <p>The library is the fftw3 (fast fourier transform) library here : </p>
  
  <p><a href="http://www.fftw.org/install/windows.html" rel="nofollow">http://www.fftw.org/install/windows.html</a></p>
  
  <p>I downloaded the folder which has three important dlls and some other header files too</p>
  
  <p>libfftw3-3.dll
  libfftw3l-3.dll
  libfftw3f-3.ll</p>
  
  <p>But I'm at a loss as to what to do with them. </p>
  
  <p>I have C++ code from another author that requires the library, and when I run</p>
  
  <p><code>waf configure</code>
  <code>waf build</code></p>
  
  <p>I get the error that "-libfftw3" is not found.</p>
  
  <p>I have already put the directory where the dlls are into my Windows path, and this seems like such a simple problem but I can't figure out how to get the compiler to find the pre-compiled DLLs. (I also tried just having the gcc compiler do a default search without specifying a library but it said "fftw.h" not found, which is strange because I already put that directory in my path.</p>
  
  <p>Any help would be appreciated; I did read the website's instructions but for Windows it only tells you to use some commands for Visual Studio (but I'm not using that compiler) and I have browsed other sites for similar issues but I can't find a solution to this specific issue.</p>