title: Cython - converting list of strings to char **
body: <p>How can I convert a python list of python strings to a null-terminated <code>char**</code> so I can pass it to external C function?</p>
  
  <p>I have:</p>
  
  <pre><code>struct saferun_task:
      saferun_jail   *jail
      saferun_limits *limits
  
      char **argv
      int stdin_fd  
      int stdout_fd
      int stderr_fd
  
  int saferun_run(saferun_inst *inst, saferun_task *task, saferun_stat *stat)
  </code></pre>
  
  <p>in cdef extern block</p>
  
  <p>I want to convert something like <code>('./a.out', 'param1', 'param2')</code>
  to something that I can assign to <code>saferun_task.argv</code></p>
  
  <p>How?</p>