On 22.07.2014 20:44, Andrey Chernov wrote:
> Producing physical writes on ftell cause great performance degradation.
> You should check for __SAPP flag before calling sflush to do this only
> for append-mode files.
BTW, I believe that sflush() should be completely eliminated even for
_SAPP case. Something like that instead:
if (fp->_flags & __SAPP) {
pos = _sseek(fp, (fpos_t)0, SEEK_END);
if (pos == -1)
return (1);
} else if (fp->_flags & __SOFF)
pos = fp->_offset;
else {
pos = _sseek(fp, (fpos_t)0, SEEK_CUR);
if (pos == -1)
return (1);
}
>
> On 22.07.2014 20:19, Pedro F. Giffuni wrote:
>> Author: pfg
>> Date: Tue Jul 22 16:19:01 2014
>> New Revision: 268984
>> URL: http://svnweb.freebsd.org/changeset/base/268984
>>
>> Log:
>> ftello: return 1 when seeking offset on an append stream.
>>
>> Obtained from: Apple Inc. (Libc 997.90.3)
>> Phabric: D442
>> MFC after: 2 weeks
>>
>> Modified:
>> head/lib/libc/stdio/ftell.c
>>
>> Modified: head/lib/libc/stdio/ftell.c
>> ==============================================================================
>> --- head/lib/libc/stdio/ftell.c Tue Jul 22 16:10:56 2014
>> (r268983)
>> +++ head/lib/libc/stdio/ftell.c Tue Jul 22 16:19:01 2014
>> (r268984)
>> @@ -97,6 +97,8 @@ _ftello(FILE *fp, fpos_t *offset)
>> * Find offset of underlying I/O object, then
>> * adjust for buffered bytes.
>> */
>> + if (__sflush(fp)) /* may adjust seek offset on append stream */
>> + return (1);
>> if (fp->_flags & __SOFF)
>> pos = fp->_offset;
>> else {
>>
>
>
--
http://ache.vniz.net/
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