PHP Detecting the Host Platform
Now let's look at how PHP interacts with the web server's host environment.
Detecting the Host Platform
Because different types of systems have different sets of host commands available, if you are writing a script that could potentially be executed on different platforms, it's useful to detect what kind of web server is being used.
The constant PHP_OS contains a string that represents the operating system. The most common reason for checking this is to find out whether a script is running on a Windows platformafter all, most Unix-like systems, and even Mac OS, behave in a very similar way.
The value of PHP_OS on a Windows web server could be Windows, WINNT, or WIN32, and in the future, other values may come into existence. Therefore, to test for a Windows platform, you should perform a non-case-sensitive comparison on the first three characters of the string. The following condition shows just one of the ways you can do this:
if (strtoupper(substr(PHP_OS, 0, 3)) == "WIN") {
...
}
Darwin Be cautious to check only that the value of PHP_OS begins with WIN, as modern versions of Mac OS report themselves as Darwin.
