Where is the man page of python library

[Steven D'Aprano]

On Thu, 22 Jul 2010 20:18:43 -0700, march wrote:

> Hi, guys.
> 
> As a regular user of python, I am often annoyed by the fact that the
> official python docementation is too short and too simple to satisfy my
> requirement.

Python is a volunteer effort. If the docs don't suit your requirements, 
we're grateful for patches.

> While working with socket, I want to know every detail about every API. 
> I can easilly achieve that by reading man page if the language is C. But
> It seems that the Python story is different.

Python is open source. Where the documentation is silent, the ultimate 
authority is the source code. Particularly if the code is a thin wrapper 
around the C library, which I expect (but don't know for sure) the socket 
code will be.


> For the interface recv(), all I got is only three sentences. "
> Receive data from the socket. The return value is a string representing
> the data received. The maximum amount of data to be received at once is
> specified by bufsize. "
> http://docs.python.org/library/socket.html#socket.socket.recv
> 
> What if the call fail? 

You will get an exception, just like the page says:

    All errors raise exceptions. The normal exceptions for 
    invalid argument types and out-of-memory conditions can be 
    raised; errors related to socket or address semantics raise 
    the error socket.error.


> What if the peer close the socket? 

You will get an exception, just like the Fine Manual says.



> What is the
> difference between blocking and non-blocking socket? 

Python isn't a tutor for basic programming concepts like sockets. That's 
what Google is for :)

But having said that, the documentation does explain the difference:

    In non-blocking mode, if a recv() call doesn’t find any data, 
    or if a send() call can’t immediately dispose of the data, 
    a error exception is raised; in blocking mode, the calls block 
    until they can proceed.

http://docs.python.org/library/socket.html#socket.socket.setblocking


> How could I get the errno or exception?

You get the exception the same way you get *every* exception: by catching 
it with a try...except block. If you don't know that, you need to learn 
the basics and not blame the documentation.

Untested, but this probably will work:

try:
    something_involving_sockets()
except socket.error, e:
    if len(e.args) == 1:
        print "Error message is:", e.args[0]
    else:
        print "errno =", e.args[0]
        print "Error message is:", e.args[1]


> All the answers are "No comment".
> 
> I hate this documentation!

Don't blame the documentation for your failure to read it. It's true that 
it could be improved, but most of your questions were answered by the 
page you linked to.



-- 
Steven