Re: [bug] Crazy I/O

[Earnie Boyd <earnie_boyd@yahoo.com>]

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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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#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] );
    }
  }
}