title: A problem with System.DllNotFoundException in the dll file created by including ippiFFTGetSize_C_32fc ().(intel IPP)
body: <p>I created a <code>dll</code> created using the <code>IPP function ippiFFTGetSize_C_32fc ()</code>.<br>
  Referencing this dll file from wpf project (c #) results in <code>System.DllNotFoundException: Unable to load DLL 'TEST.dll'</code> error.</p>
  
  <pre><code>int HioTest(Ipp32fc* csSrcImg, Ipp32fc* csDstImg)
  {
  
      // FFT Init
      IppiFFTSpec_C_32fc  *pSpec = NULL;                              /* Pointer to FFT spec structure */
      Ipp8u               *pMemInit = NULL, *pBuffer = NULL;          /* Pointer to the work buffers */
      int                 sizeSpec = 0, sizeInit = 0, sizeBuf = 0;    /* Size of FFT spec structure, init and work buffers */
      int               order = 9;
  
      ippiFFTGetSize_C_32fc(order, order, IPP_FFT_DIV_INV_BY_N, ippAlgHintAccurate, &amp;sizeSpec, &amp;sizeInit, &amp;sizeBuf);
  
      return 5;
  }
  </code></pre>
  
  <p>I created a <code>TEST.dll</code> (C language) using IPP for External library. I want to refer to <code>TEST.dll</code> in my wpf project and use it.</p>
  
  <p>The tool used is "visual studio 2017" and the IPP version uses the latest version of <code>compilers_and_libraries_2019.1.144</code>.</p>
  
  <p>See the IPP documentation. The settings of the dll project,</p>
  
  <ul>
  <li>Debug / x64  </li>
  <li>Add <code>ippsmt.lib, ippcoremt.lib</code> for <code>Additional Dependencies</code>.  </li>
  <li>Automatic "single-threaded DLL" setting.  </li>
  <li><code>export .def</code> created.  </li>
  <li>Add <code>ippInit ()</code> to dllmain.cpp  </li>
  <li>Referencing from C # . /clr setting  </li>
  </ul>
  
  <p>C # project</p>
  
  <ul>
  <li>Debug / x64  </li>
  <li>unlock the loader  </li>
  <li>Increase the reserve stack size</li>
  </ul>
  
  <p>I set it up like this.</p>
  
  <p><code>Other ippMalloc (), ippsAdddC_32f_I ()</code></p>
  
  <p>The <code>dll</code> file I created using the above worked properly in my wpf project. However, TEST.dll containing <code>ippiFFTGetSize_C_32fc ()</code> will result in an error <code>System.DllNotFoundException: Unable to load DLL 'TEST.dll'</code>.
  I want to know the cause or solution.</p>