ID:               22362
 Updated by:       [EMAIL PROTECTED]
 Reported By:      php at codewhore dot org
-Status:           Open
+Status:           Assigned
 Bug Type:         Filesystem function related
 Operating System: Linux 2.4
 PHP Version:      4.3.1
-Assigned To:      
+Assigned To:      wez


Previous Comments:
------------------------------------------------------------------------

[2003-02-21 14:43:43] php at codewhore dot org

I've verified that this behavior still exists in today's snapshot
(php4-STABLE-200302212030.tar.gz).

------------------------------------------------------------------------

[2003-02-21 13:58:03] php at codewhore dot org

In PHP:

<?php
  $fp = fopen('./foo', 'w+');
  fwrite($fp, 'quxbar', 6);
  fseek($fp, 3, SEEK_SET);
  fread($fp, 1);
  fseek($fp, 4, SEEK_SET);
  fwrite($fp, '!', 1);
  fseek($fp, 0, SEEK_SET);
  $buf = fread($fp, 4095);
  echo "$buf\n";
?>

In C:

#include <stdio.h>

int main()
{
  static char buf[4096];
  FILE *f = fopen("./foo", "w+");
  fwrite("quxbar", 6, 1, f);
  fseek(f, 3, SEEK_SET);
  fread(&buf, 1, 1, f);
  fseek(f, 4, SEEK_SET);
  fwrite("!", 1, 1, f);
  fseek(f, 0, SEEK_SET);
  fread(&buf, 4095, 1, f);
  printf("%s\n", buf);
  return 0;
}

The PHP version outputs 'quxbar!.
The C version outputs 'quxb!r'.

In fact, for any PHP code of the structure:
<?php
  fseek($fp, $x, SEEK_SET);
  fread($fp, $n);
  fseek($fp, $y, SEEK_SET);
  fwrite($fp, '!', 1);
?>

the data from the fwrite always gets written to the end of the stream
when $x < $y and $n is exactly 1. I can reproduce this with different
whence parameters, but it seems to only happen with a seek followed by
a single-byte read.

------------------------------------------------------------------------


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