<?
/*
* Check that a file is a GIF89
/
$filename = "php.gif";
$fp = fopen($filename, "r");
//get first 128 bytes
$data = fread($fp, 128);
//close file
fclose($fp);
//check for GIF89
if(substr($data, 0, 5) == "GIF89")
{
print("$filename is a GIF89 file.\n");
}
else
{
print("$filename isn't a GIF89 file.\n");
}
?>
integer fseek(integer file_handle, integer offset)
To change PHP's internal file pointer, use fseek. It expects a valid file handle as created
by fopen. It also expects an offset, the number of bytes past the beginning of the file. If
an error occurs, fseek returns negative one (-1); otherwise it returns zero (0). Take note
that this is different from most other PHP functions.
Seeking past the end of the file is not an error; however, using fseek on a file opened by
fopen if it was used with http:// or ftp:// is forbidden.
If you need to know where the file pointer points, use the ftell function.
<?
// open a file
if($myFile = fopen("data.txt", "r"))
{
// jump 32 bytes into the file
fseek($myFile, 32);
// dump the rest of the file
fpassthru($myFile);
}
else
{