Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

DIRECTORY_SEPARATOR (string)
PATH_SEPARATOR (string): Available since PHP 4.3.0. Semicolon on Windows, colon otherwise.
SCANDIR_SORT_ASCENDING (integer): Available since PHP 5.4.0.
SCANDIR_SORT_DESCENDING (integer): Available since PHP 5.4.0.
SCANDIR_SORT_NONE (integer): Available since PHP 5.4.0.

User Contributed Notes

Anonymous

2 years ago


In PHP 5.6 you can make a variadic function.

<?php
/**
 * Builds a file path with the appropriate directory separator.
 * @param string $segments,... unlimited number of path segments
 * @return string Path
 */
function file_build_path(...$segments) {
    return join(DIRECTORY_SEPARATOR, $segments);
}

file_build_path("home", "alice", "Documents", "example.txt");
?>

In earlier PHP versions you can use func_get_args.

<?php
function file_build_path() {
    return join(DIRECTORY_SEPARATOR, func_get_args($segments));
}

file_build_path("home", "alice", "Documents", "example.txt");
?>

Anonymous

2 years ago


For my part I'll continue to use this constant because it seems more future safe and flexible, even if Windows installations currently convert the paths magically. Not that syntax aesthetics matter but I think it can be made to look attractive:

<?php
$path = join(DIRECTORY_SEPARATOR, array('root', 'lib', 'file.php');
?>

Paulo Marques

2 years ago


DIRECTORY_SEPARATOR is not necessarily needed, PHP always converts / to the appropriate character in its file functions.
It is good practice, though.

orlov0562 at gmail dot com

9 months ago


While debugging, this function return error number and it's difficult to remember all errors codes, so I think it's should be there.

<?php
print_r([
    'PREG_NO_ERROR' => PREG_NO_ERROR,
    'PREG_INTERNAL_ERROR' => PREG_INTERNAL_ERROR,
    'PREG_BACKTRACK_LIMIT_ERROR' => PREG_BACKTRACK_LIMIT_ERROR,
    'PREG_RECURSION_LIMIT_ERROR' => PREG_RECURSION_LIMIT_ERROR,
    'PREG_BAD_UTF8_ERROR' => PREG_BAD_UTF8_ERROR,
    'PREG_BAD_UTF8_OFFSET_ERROR' => PREG_BAD_UTF8_OFFSET_ERROR,
]);
?>

Result:

Array
(
    [PREG_NO_ERROR] => 0
    [PREG_INTERNAL_ERROR] => 1
    [PREG_BACKTRACK_LIMIT_ERROR] => 2
    [PREG_RECURSION_LIMIT_ERROR] => 3
    [PREG_BAD_UTF8_ERROR] => 4
    [PREG_BAD_UTF8_OFFSET_ERROR] => 5
)

Harrison

10 months ago


DIRECTORY_SEPARATOR is a lifesaver! A hacker must never know what php files you have included into your php webpages or your php scripts that javascript calls upon. If you were to use '/' to include a file, the hacker can instantly know that the file you included is there, however, if you use DIRECTORY_SEPARATOR then the hacker would not know the file has been included.