From: Eric Hodel <drbrain@...7.net>
Date: 2007-01-29T18:54:36+09:00
Subject: Re: Net::HTTP Closes STDIN

On Jan 27, 2007, at 22:01, James Edward Gray II wrote:
> On Jan 27, 2007, at 8:48 PM, Eric Hodel wrote:
>> On Jan 27, 2007, at 18:38, James Edward Gray II wrote:
>>> On Jan 27, 2007, at 7:39 PM, Eric Hodel wrote:
>>>
>>>> $stdin isn't closed, its at the end of file.  Use #closed? to  
>>>> test if an IO has been closed or not.
>>>
>>> Right, good point.
>>>
>>> However, when I call eof?() before the Net::HTTP call it behaves  
>>> differently (stalls and prints false).  Why does it not behave  
>>> the same after that page read?
>>
>> $ ruby test.rb
>> closed? false
>> type some text here
>> eof? false
>> closed? false
>> eof? false
>> $
>>
>> For the first #eof? no data written, so Ruby waits until  
>> something's been flushed.
>
> OK, that makes sense.  However, why does moving that eof?() check  
> below a Net::HTTP page fetch change this?

I don't see this behavior.  With your original example I have to hit  
^D to get a prompt back.

$ ruby -v
ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-darwin8.8.2]

> In that case, why does Ruby not need for something to be flushed

Because #eof? reads a character if feof(3) is not true and there's no  
data pending:

rb_io_eof(io)
     VALUE io;
{
     OpenFile *fptr;
     int ch;

     GetOpenFile(io, fptr);
     rb_io_check_readable(fptr);

     if (feof(fptr->f)) return Qtrue;
     if (READ_DATA_PENDING(fptr->f)) return Qfalse;
     READ_CHECK(fptr->f);
     clearerr(fptr->f);
     TRAP_BEG;
     ch = getc(fptr->f);
     ^^^^^^^^^^^^^^^^^^^

Analysis of sampling pid 15640 every 10.000000 milliseconds
Call graph:
[...]
  300 rb_io_eof
    300 getc
[...]

> in that case and why is eof?() then +true+?

#eof? will only be true when there's no more data to read.

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!