Re: [9fans] APE select() and awkward Python subprocess PIPEfitting

[Jeff Sickel <jas@corpus-callosum.com>]

Actually, that printf was for my debugging:

diff /sys/src/ape/lib/ap/plan9/_buf.c _buf.c
294a295
> /*
298c299
< 				errno = EBADF;		/* how X tells a client is gone */
---
> 				errno = EBADF;		// how X tells a client is gone
300a302
> */


On Feb 25, 2013, at 8:29 PM, Jeff Sickel <jas@corpus-callosum.com> wrote:

> I've been tracking down little errors in the APE select() function that cropped up when trying to use Python's subprocess module.  After a few too many hours of investigation, I've come to the conclusion that the code that causes error is intentional code to handle a specific case for X (I'll assume X11 until corrected):
> 
> ; diff /sys/src/ape/lib/ap/plan9/_buf.c _buf.c
> 292a293
>> printf("no buffered %d\n", i);
> 294a296
>> /*
> 298c300
> < 				errno = EBADF;		/* how X tells a client is gone */
> ---
>> 				errno = EBADF;		// how X tells a client is gone
> 300a303
>> */
> 
> 
> 
> By removing the above, Python code that uses subprocess.Popen(cmd, stdout=PIPE, stderr=PIPE) will now work correctly, without having to resort to os.popen3(cmd) attempts to get around the select.error: (4, 'Bad file number') that would crop up without the change.
> 
> My question is: does anyone still use the X11 code based on APE?  Is this section safe to remove in sources?  Or do you have additional recommendations to work around the select() error?
> 
> If not, I'll prep a patch.  Thanks.
> 
> -jas
> 
>