(PHP 5 >= 5.4.0, PHP 7)
trait_exists — 锟斤拷锟街革拷锟斤拷锟� trait 锟角凤拷锟斤拷锟�
$traitname
[, bool $autoload
] ) : bool
traitname锟斤拷锟斤拷锟斤拷 trait 锟斤拷锟斤拷锟斤拷
autoload锟斤拷锟斤拷锟轿达拷锟斤拷兀锟斤拷欠锟绞癸拷锟斤拷远锟斤拷锟斤拷兀锟絘utoload锟斤拷锟斤拷
锟斤拷锟� trait 锟斤拷锟节凤拷锟斤拷 TRUE锟斤拷锟斤拷锟斤拷锟斤拷锟津返伙拷 FALSE锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟绞憋拷蚍祷锟� NULL锟斤拷