title: How to allocate empty CString?
body: <p>The cFunctionCall populates b and I am able to get content of string into GO string. However, I think that my memory allocation (line #1) is not efficient.</p>
  
  <pre><code>b := C.CString(strings.Repeat(" ", 50))
  defer C.free(unsafe.Pointer(b))
  C.cFunctionCall(b, 50)
  rs := C.GoString(b)
  log.Printf("rs: '%v'\n", rs)
  </code></pre>