Re: full_read depends on incoming errno

[Andy Wingo]

Hi,

On Tue 19 Feb 2013 22:25, Paul Eggert <address@hidden> writes:

> On 02/19/13 13:15, Eli Zaretskii wrote:
>>     if (full_read (fd, cookie, sizeof cookie) != sizeof cookie
>>      || full_read (fd, SCM_BYTEVECTOR_CONTENTS (bv),
>>                    SCM_BYTEVECTOR_LENGTH (bv)) != SCM_BYTEVECTOR_LENGTH (bv))
>>       {
>>         int errno_save = errno;
>>         (void) close (fd);
>>         errno = errno_save;
>>         SCM_SYSERROR;
>>       }
>> 
> ...
>> If the file is too short for these two reads, then errno will have
>> some random value (because full_read "succeeded" as far as that
>> function is concerned), and the error message in SCM_SYSERROR will
>> display something utterly unrelated
>
> Yes, full_read should return a short value and set errno to 0,
> so errno_save should be zero.  If SCM_SYSERROR displays
> a seemingly-unrelated diagnostic like "Error 0", that would
> explain the problem.
>
>> I think it's a Guile
>> problem, since from gnulib POV, nothing went wrong in that call.
>
> Yes, that sounds right.

You are both right, yes.  Thanks for the help and sorry for the
confusion.

Cheers,

Andy
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