[Web-SIG] some questions about start_response implementation

[Manlio Perillo]

Hi.

I'm implementing the start_response callable for Nginx mod_wsgi and I 
have a few questions.

1) From the WSGI PEP it seems that an implementation is allowed to
    *always* raise an exception when start_response is called with a not
    null exc_info.

    Is this true?

2) What happens if an application call start_response with an incorrect
    status line or headers?

    Should an implementation consider the function "called", so that an
    application can call it a second time, *without* the exc_info
    parameter?

3) How many applications/frameworks use the exc_info parameter for
    start_response?


Thanks  Manlio Perillo