Attempts to change the mode of the file specified by filename to that given in mode.
Note that mode is not automatically assumed to be an octal value, so strings (such as "g+w") will not work properly. To ensure the expected operation, you need to prefix mode with a zero (0):
chmod ("/somedir/somefile", 755); // decimal; probably incorrect chmod ("/somedir/somefile", "u+rwx,go+rx"); // string; incorrect chmod ("/somedir/somefile", 0755); // octal; correct value of mode
Returns TRUE on success, FALSE on failure.
Note: This function is not implemented on Windows platforms.