iconv

// : iconv(string $in_charset, string $out_charset,string $string):string
// str $in_charset  $out_charset  
$text ="This is the Euro symbol '€'.";

echo 'Original : ',$text,PHP_EOL; // Original :This is the Euro symbol '€'.

echo 'TRANSLIT: ',iconv("UTF-8","ISO-8859-1//TRANSLIT",$text),PHP_EOL;//  TRANSIT:This is the Euro symbol 'EUR'.

echo 'IGNORE :',iconv("UTF-8","ISO-8859-1//IGNORE",$text),PHP_EOL;//  IGNORE:This is the Euro symbol ''.

echo 'Plain  :' iconv("UTF-8","ISO-8859-1",$text),PHP_EOL; //  Plain:
Notice: iconv(): Detected an illegal character in input string in .\iconv-example.php on line 7  

uniqid

//  uniqid ([string $prefix=""[,bool $more_entropy=false]]):string
// 、 ID。
printf("uniqid(): %s\r
",uniqid()); // :uniqid:5c7164526938c

printf("uniqid('php_'): %s\r
",uniqid('php_'));//uniqid('php_'):php_5c7164ea6d5c7

printf("uniqid('',true):  %s\r
",uniqid('',true));//  uniqid('',true) :5c71654843ab76.86224870

gettype

 :Warning!   gettype()  ， 。 ， ， 。

settype

// :settype(mixed &$var,string$type):bool
// var $type.
$foo="5bar";//string
$bar=true;//bollean
$settype($foo,'integer');// foo :int(5)
$settype($bar,'string');//$bar:string(1);

getcwd

// :getcwd(void):string
// 
echo getcwd()."
";// ：/home/didou
chdir('cvs');
echo getcwd() . "
"; //   ：/home/didou/cvs