title: find_library() in ctypes
body: <p>I am trying to use the command find_library() from ctypes but I'm getting an error that I don't understand its reason. I am working on Windows</p>
  
  <p>This is the code:</p>
  
  <pre><code>import ctypes
  from ctypes.util import find_library
  import numpy
  from string import atoi
  from time import sleep
  
  # Class constants
  #nidaq = ctypes.windll.nicaiu
  nidaq  = ctypes.cdll.LoadLibrary(find_library('NIDAQmx'))
  </code></pre>
  
  <p>And this is the error I'm getting:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;pyshell#4&gt;", line 1, in &lt;module&gt;
      nidaq  = ctypes.cdll.LoadLibrary(find_library('NIDAQmx'))
    File "C:\Python27\lib\ctypes\__init__.py", line 443, in LoadLibrary
      return self._dlltype(name)
    File "C:\Python27\lib\ctypes\__init__.py", line 365, in __init__
      self._handle = _dlopen(self._name, mode)
  TypeError: expected string or Unicode object, NoneType found
  </code></pre>
  
  <p>Should I place NIDAQmx in a specific place for example so that it can be found? Or this is unrelated? </p>
  
  <p>Thanks!</p>