title: How to force tesseract not to use TESSDATA_PREFIX
body: <p>I had tesseract installed on my pc, and it defined TESSDATA_PREFIX enviroment variable.  After complete uninstallation of tesseract, i try to use tesseract API in this way:</p>
  
  <pre><code>if (myOCR-&gt;Init("C:/Projects/project/Release/tessdata/", "rus")) {
              fprintf(stderr, "Could not initialize tesseract.\n");
              exit(1);
          }
  </code></pre>
  
  <p>and recieve</p>
  
  <pre><code>Error opening data file C:\Program Files (x86)\Tesseract-OCR\tessdata/rus.traine
  ddata
  Please make sure the TESSDATA_PREFIX environment variable is set to the parent d
  irectory of your "tessdata" directory.
  Failed loading language 'rus'
  Tesseract couldn't load any languages!
  Could not initialize tesseract.
  </code></pre>
  
  <p>typing set TESSDATA_PREFIX in cmd gives me that there is no such variable. But tesseract remembers it (don't know how). So how can i force tesseract to search traindata in concrete folder? Thanks</p>