* Re: [bug] Crazy I/O. -cont.
@ 1999-03-08 14:10 Michael V. Nikolaev
1999-03-31 19:45 ` Michael V. Nikolaev
0 siblings, 1 reply; 2+ messages in thread
From: Michael V. Nikolaev @ 1999-03-08 14:10 UTC (permalink / raw)
To: earnie_boyd, cygwin users
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I took a look at implementation of FILE structure in newlib/libc/include/sys/reent.h (src distribution). It contains the field -offset:
struct __sFILE {
...
int _offset; /* current lseek offset */
...
};
Struct FILE typedef'ed as __sFILE. So, there exist two file offset references: one for streams, another for block I/O. I think, block I/O is based on WinAPI file I/O. Stream I/O should be built, in general, on block I/O level. And when you use lseek() the resulting file offset is not sinchronized with the file offset field in the respective stream structure (*stdin, in your case) because block I/O knows nothing about stream I/O.
Regards,
Micahel
-----Original Message-----
From: Earnie Boyd <earnie_boyd@yahoo.com>
To: Michael V. Nikolaev <mvn@gu.kiev.ua>; cygwin users <cygwin@sourceware.cygnus.com>
Date: 8 áåðåçÃÿ 1999 ð. 21:45
Subject: Re: [bug] Crazy I/O.
>---"Michael V. Nikolaev" <mvn@gu.kiev.ua> wrote:
>>
>>
>> -----Original Message-----
>> From: Earnie Boyd <earnie_boyd@yahoo.com>
>> To: cygwin users <cygwin@sourceware.cygnus.com>
>> Date: 8 áåðåçÃÿ 1999 ð. 18:46
>> Subject: [bug] Crazy I/O.
>>
>>
>> Hi!
>>
>> You use stdin as a _stream_ when calling gets(). So, try to call
>fseek(stdin, 0L, SEEK_SET) after the second dup2(). It should work.
>>
>
>Didn't help. Besides, it shouldn't be needed.
>==
>- \\||//
>-------------------o0O0--Earnie--0O0o-------------------
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [bug] Crazy I/O. -cont.
1999-03-08 14:10 [bug] Crazy I/O. -cont Michael V. Nikolaev
@ 1999-03-31 19:45 ` Michael V. Nikolaev
0 siblings, 0 replies; 2+ messages in thread
From: Michael V. Nikolaev @ 1999-03-31 19:45 UTC (permalink / raw)
To: earnie_boyd, cygwin users
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 2144 bytes --]
I took a look at implementation of FILE structure in newlib/libc/include/sys/reent.h (src distribution). It contains the field -offset:
struct __sFILE {
...
int _offset; /* current lseek offset */
...
};
Struct FILE typedef'ed as __sFILE. So, there exist two file offset references: one for streams, another for block I/O. I think, block I/O is based on WinAPI file I/O. Stream I/O should be built, in general, on block I/O level. And when you use lseek() the resulting file offset is not sinchronized with the file offset field in the respective stream structure (*stdin, in your case) because block I/O knows nothing about stream I/O.
Regards,
Micahel
-----Original Message-----
From: Earnie Boyd <earnie_boyd@yahoo.com>
To: Michael V. Nikolaev <mvn@gu.kiev.ua>; cygwin users <cygwin@sourceware.cygnus.com>
Date: 8 áåðåçÃÿ 1999 ð. 21:45
Subject: Re: [bug] Crazy I/O.
>---"Michael V. Nikolaev" <mvn@gu.kiev.ua> wrote:
>>
>>
>> -----Original Message-----
>> From: Earnie Boyd <earnie_boyd@yahoo.com>
>> To: cygwin users <cygwin@sourceware.cygnus.com>
>> Date: 8 áåðåçÃÿ 1999 ð. 18:46
>> Subject: [bug] Crazy I/O.
>>
>>
>> Hi!
>>
>> You use stdin as a _stream_ when calling gets(). So, try to call
>fseek(stdin, 0L, SEEK_SET) after the second dup2(). It should work.
>>
>
>Didn't help. Besides, it shouldn't be needed.
>==
>- \\||//
>-------------------o0O0--Earnie--0O0o-------------------
>-- earnie_boyd@yahoo.com --
>-- http://www.freeyellow.com/members5/gw32/index.html --
>----------------------ooo0O--O0ooo----------------------
>
>PS: Newbie's, you should visit my page.
>_________________________________________________________
>DO YOU YAHOO!?
>Get your free @yahoo.com address at http://mail.yahoo.com
>
\vKCBÂÃ[Â\b\x1d^[Ã\x1d[ÂÃXÂÃÃÂXÂH\x19ÂÂÃH\x1d\x1a\x1a\Ã^[\x1a\Ã\x0fÃBÂÃ[Â\b\x18H^[Y\ÃÃYÃH\x1d^[Ã\x18ÃYÃÃ[Â][ÂÃXÂÃÃÂXÂP\x1cÃÃ\ÂÃ]Ã\ÂKÂÃYÃÂ\ÃÂÃÃCB
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