I build a Visual Studio solution from a Python script. Everything works nicely, except that I am unable to capture the build output.

```
p = subprocess.Popen(['devenv', 'solution.sln', '/build'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
(out, err) = p.communicate()
ret = p.returncode

```

Here, both `out` and `err` are always empty. This happens regardless of the build success as seen in `p.returncode`.