Description:
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For Windows, the is_executable() function only checks the file extensions of exe, com, bat and cmd.

This is incomplete.

Within Windows, there is an environment variable called PATHEXT. This contains a list of extensions which are executable.

If you type a program whose extension is in this list and the program with that extension is in the path, then it is executed.

You can easily add .PHP to this list (see UserNote http://www.php.net/manual/en/features.commandline.php#53252). This is completely normal behaviour on windows.

Using the "FileTypes" mechanism allows any type of file to have an automatic "handler" (double click a PDF file and Acrobat loads with that file). By also adding the extension to the PATHEXT environment variable you can type just the name at the CLI and the lovely windows magic happens automagically.

The standard list of executable types within windows XP is:

PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH

Mine is:

PATHEXT=.COM;.EXE;.BAT;.CMD;.PHP;.PYC;.PY;

I don't deal with MS VB scripts, but I do deal with PHP and Python!

All of these are "executable" (i.e. the behaviour of an abc.php is the same as an abc.bat or an abc.exe).

Admittedly this is only on windows, but the current method should either be documented as only being of limited use on Windows (with the  4 types) or be extended to look at the Windows mechanism (just like I assume the *ix version looks at an executable bit on the permissions?).

The following is a screen grab to prove the point.

12/04/2007 15:02:28 C:\>type "d:\PHP Quickies\isexec.php"
<?php
echo $argv[0], ' is ', (is_executable($argv[0]) ? '' : 'not '), 'executable';
?>

12/04/2007 15:02:34 C:\>set path
Path=C:\Batch;C:\PHP5;D:\PHP Quickies;C:\Program Files\Windows Resource Kits\Tools;C:\Python\Lib;C:\Program Files\WinRAR;D:\Sage\UTILS;c:\program files\imagemagick;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\Universal Extractor\bin;C:\Program Files\Microsoft SQL Server\80\Tools\BINN;C:\Program Files\Nmap;D:\Cygwin\bin;
PATHEXT=.COM;.EXE;.BAT;.CMD;.PHP;.PYC;.PY;.VBS;.VBE;.JS;.JSE;.WSF;.WSH

12/04/2007 15:02:37 C:\>isexec
D:\PHP Quickies\isexec.php is not executable



Reproduce code:
---------------
<?php
echo is_executable($argv[0]) ? 'Executable' : 'Not executable';
?>

Expected result:
----------------
D:\PHP Quickies\isexec.php is executable

Actual result:
--------------
D:\PHP Quickies\isexec.php is not executable