[bug] Crazy I/O.

[bug] Crazy I/O.

[Earnie Boyd]

This bug has to do with getting back to the beginning of a file.  I was trying to test what happens with O_TEXT and O_BINARY based upon the CYGWIN variable and the [no]binmode value.  I'm using the 1998-12-3 release of the cygwin1.dll on NT4SP3.  I haven't tested with a recent snapshot but the list needs to know about this for the distributed version.

I've included a test case.  You must save the file as text.tst.c, gcc -o text text.tst.c, and have your working directory set to the source code.


==
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[bug] Crazy I/O.

[Earnie Boyd]

[-- Attachment #1: Type: text/plain, Size: 938 bytes --]

This bug has to do with getting back to the beginning of a file.  I was trying to test what happens with O_TEXT and O_BINARY based upon the CYGWIN variable and the [no]binmode value.  I'm using the 1998-12-3 release of the cygwin1.dll on NT4SP3.  I haven't tested with a recent snapshot but the list needs to know about this for the distributed version.

I've included a test case.  You must save the file as text.tst.c, gcc -o text text.tst.c, and have your working directory set to the source code.


==
-                        \\||//
-------------------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.
_________________________________________________________
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[-- Attachment #2: text.tst.c --]
[-- Type: text/x-c, Size: 1055 bytes --]

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <io.h>

int
main (void)
{
  int fh1, fh2;
  unsigned int nbytes = 60000, bytesread;
  char fh1_IN[60000];
  fh1 = open( "text.tst.c", O_RDONLY | O_TEXT );
  dup2(fh1, 0);
  gets( fh1_IN );
  bytesread = strlen(fh1_IN);
  printf( "read %u bytes from file\n", bytesread );
  {
    unsigned int i;
    for (i=0; i< bytesread; i++) {
      printf( "char value: %i\t\t%c\n", fh1_IN[i], fh1_IN[i] );
    }
  }
  close( fh1 );

  fh1 = open( "text.tst.c", O_RDONLY | O_BINARY );
  lseek( fh1, 0, SEEK_SET ); /* added to try to get the pointer back to the
                                the beginning of the file.  Which doesn't help.
                             */
  dup2(fh1, 0);
  gets( fh1_IN );
  bytesread = strlen(fh1_IN);
  printf( "read %u bytes from file\n", bytesread );
  {
    unsigned int i;
    for (i=0; i< bytesread; i++) {
      printf( "char value: %i\t\t%c\n", fh1_IN[i], fh1_IN[i] );
    }
  }
  close( fh1 );
}

Re: [bug] Crazy I/O

[Earnie Boyd]

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I've modified the text.tst.c test program based on suggestions from the list as noted in the program.  Note this demonstrates a bug where the values for the file descriptor are not reset if the same file descriptor is used.

I can also state that the 19990115 snapshot eliminates the WARNING listed in the Users Guide under "the default Cygwin behavior" concerning the processing mode always being binary even if O_TEXT was specified if the default is binary.

Earnie.
P.S. BCC: developers
---

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[-- Attachment #2: text.tst.c --]
[-- Type: text/x-c, Size: 1633 bytes --]

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <io.h>

/*
   text.tst.c
   Version 2
*/

int
main (void)
{
  int fh1, fh2;
  unsigned int nbytes = 60000, bytesread;
  char fh1_IN[60000];
  fh1 = open( "text.tst.c", O_RDONLY | O_TEXT );
  dup2(fh1, 0);
  close( fh1 );
  gets( fh1_IN );
  bytesread = strlen(fh1_IN);
  printf( "read %u bytes from file\n", bytesread );
  {
    unsigned int i;
    for (i=0; i< bytesread; i++) {
      printf( "char value: %i\t\t%c\n", fh1_IN[i], fh1_IN[i] );
    }
  }

  fh1 = open( "text.tst.c", O_RDONLY | O_BINARY );
  dup2(fh1, 0);
  close( fh1 );

  /* 
  ** I first tried: lseek( 0, 0, SEEK_SET ) but that didn't help.  
  ** Michael V. Nikolaev <mvn@gu.kiev.ua> suggested using fseek which does
  ** reset the file descriptor and stream.  Note, without this the change
  ** from O_TEXT to O_BINARY doesn't take effect either.  If you remove the
  ** fseek then the file descriptor doesn't get reset to the beginning of the
  ** file as it should and the processing mode remains in O_TEXT.
  ** 
  ** The fseek shouldn't be needed but works around a bug.
  **
  ** I tried adding the close( 0 ) and fclose( stdin ) but that caused the
  ** fseek function not to work obviously because the stream was closed.
  **
  */

  fseek( stdin, 0L, SEEK_SET );
  
  
  gets( fh1_IN );
  bytesread = strlen(fh1_IN);
  printf( "read %u bytes from file\n", bytesread );
  {
    unsigned int i;
    for (i=0; i< bytesread; i++) {
      printf( "char value: %i\t\t%c\n", fh1_IN[i], fh1_IN[i] );
    }
  }
}

Re: [bug] Crazy I/O.

[Michael V. Nikolaev]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1765 bytes --]

I don't sure that it shouldn't be needed. IMHO, it depends on implementation.
BTW, it works well on my installation: NT SP4, cygwin-20.1, coolview dll, no binary mounts, CYGWIN=binmode ... . Here is the respective chunk of source:

...
 dup2(fh1, 0);
 fseek( stdin, 0L, SEEK_SET );
 gets( fh1_IN );
...

This really works.

Wishes,

Michael

-----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 áåðåçíÿ 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 áåðåçíÿ 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
>
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Re: [bug] Crazy I/O.

[Earnie Boyd]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 998 bytes --]

---"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 áåðåçíÿ 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


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Re: [bug] Crazy I/O.

[Michael V. Nikolaev]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1598 bytes --]


-----Original Message-----
From: Earnie Boyd <earnie_boyd@yahoo.com>
To: cygwin users <cygwin@sourceware.cygnus.com>
Date: 8 áåðåçíÿ 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.

Regards,
Michael



>This bug has to do with getting back to the beginning of a file.  I was trying to test what happens with O_TEXT and O_BINARY based upon the CYGWIN variable and the [no]binmode value.  I'm using the 1998-12-3 release of the cygwin1.dll on NT4SP3.  I haven't tested with a recent snapshot but the list needs to know about this for the distributed version.
>
>I've included a test case.  You must save the file as text.tst.c, gcc -o text text.tst.c, and have your working directory set to the source code.
>
>
>==
>-                        \\||//
>-------------------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
>
\vKCB•Ø[\b\x1d^[È\x1d[œÝXœØܚX™H\x19œ›ÛH\x1d\x1a\x1a\È^[\x1a\Ý\x0fÃB”Ù[™\b\x18H^[Y\ÜØYÙH\x1d^[È\x18ÞYÝÚ[‹][œÝXœØܚX™P\x1cÛÝ\˜Ù]Ø\™K˜ÞY۝\˘ÛÛCB

Re: [bug] Crazy I/O

[Earnie Boyd]

I've modified the text.tst.c test program based on suggestions from the list as noted in the program.  Note this demonstrates a bug where the values for the file descriptor are not reset if the same file descriptor is used.

I can also state that the 19990115 snapshot eliminates the WARNING listed in the Users Guide under "the default Cygwin behavior" concerning the processing mode always being binary even if O_TEXT was specified if the default is binary.

Earnie.
P.S. BCC: developers
---

_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com

Re: [bug] Crazy I/O.

[Michael V. Nikolaev]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1765 bytes --]

I don't sure that it shouldn't be needed. IMHO, it depends on implementation.
BTW, it works well on my installation: NT SP4, cygwin-20.1, coolview dll, no binary mounts, CYGWIN=binmode ... . Here is the respective chunk of source:

...
 dup2(fh1, 0);
 fseek( stdin, 0L, SEEK_SET );
 gets( fh1_IN );
...

This really works.

Wishes,

Michael

-----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 áåðåçíÿ 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 áåðåçíÿ 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
>
\x02ÒÐÐ¥v\x16çB\aFò\aVç7V'67&–&R\x06g&öÒ\aF†—2\x06Ɨ7CðÐ¥6VæB\x06\x12\x06ÖW76\x16vR\aFò\x067–wv–â×Vç7V'67&–&T\a6÷W&6Wv\x17&Ræ7–vçW2æ6öÐÐ

Re: [bug] Crazy I/O.

[Earnie Boyd]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 997 bytes --]

---"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 áåðåçíÿ 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!?
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Re: [bug] Crazy I/O.

[Michael V. Nikolaev]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1598 bytes --]


-----Original Message-----
From: Earnie Boyd <earnie_boyd@yahoo.com>
To: cygwin users <cygwin@sourceware.cygnus.com>
Date: 8 áåðåçíÿ 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.

Regards,
Michael



>This bug has to do with getting back to the beginning of a file.  I was trying to test what happens with O_TEXT and O_BINARY based upon the CYGWIN variable and the [no]binmode value.  I'm using the 1998-12-3 release of the cygwin1.dll on NT4SP3.  I haven't tested with a recent snapshot but the list needs to know about this for the distributed version.
>
>I've included a test case.  You must save the file as text.tst.c, gcc -o text text.tst.c, and have your working directory set to the source code.
>
>
>==
>-                        \\||//
>-------------------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
>
\vKCB•Ø[\b\x1d^[È\x1d[œÝXœØܚX™H\x19œ›ÛH\x1d\x1a\x1a\È^[\x1a\Ý\x0fÃB”Ù[™\b\x18H^[Y\ÜØYÙH\x1d^[È\x18ÞYÝÚ[‹][œÝXœØܚX™P\x1cÛÝ\˜Ù]Ø\™K˜ÞY۝\˘ÛÛCB