04-23-2009
First off, have you already proven that conventional I/O (read/write or stdio) is simply not adequate for your files? Buffering is your friend.
You might want to read Steven's 'Advanced Programming in the Unix Environment' -
the chapter (Chap 8, I think) with the table on the effect of buffering on I/O....
Rochkind's 'Advanced Unix Programming' has some examples of high-performance read/write routines using conventional syscalls, including mmap().
You should consider that pitching programmatically simpler methodology for more complex methodology is never always a given. What you gain in speed may not be worth the extra programming time and maintenance time. Is say, 100 extra hours of your time worth a 10% gain in performance? Your manager might say 'No'.
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LEARN ABOUT PHP
fileatime
FILEATIME(3) 1 FILEATIME(3)
fileatime - Gets last access time of file
SYNOPSIS
int fileatime (string $filename)
DESCRIPTION
Gets the last access time of the given file.
PARAMETERS
o $filename
- Path to the file.
RETURN VALUES
Returns the time the file was last accessed, or FALSE on failure. The time is returned as a Unix timestamp.
EXAMPLES
Example #1
fileatime(3) example
<?php
// outputs e.g. somefile.txt was last accessed: December 29 2002 22:16:23.
$filename = 'somefile.txt';
if (file_exists($filename)) {
echo "$filename was last accessed: " . date("F d Y H:i:s.", fileatime($filename));
}
?>
ERRORS
/EXCEPTIONS
Upon failure, an E_WARNING is emitted.
NOTES
Note
The atime of a file is supposed to change whenever the data blocks of a file are being read. This can be costly performance-wise
when an application regularly accesses a very large number of files or directories.
Some Unix filesystems can be mounted with atime updates disabled to increase the performance of such applications; USENET news
spools are a common example. On such filesystems this function will be useless.
Note
Note that time resolution may differ from one file system to another.
Note
The results of this function are cached. See clearstatcache(3) for more details.
Tip
As of PHP 5.0.0, this function can also be used with some URL wrappers. Refer to "Supported Protocols and Wrappers" to determine
which wrappers support stat(3) family of functionality.
SEE ALSO
filemtime(3), fileinode(3), date(3).
PHP Documentation Group FILEATIME(3)