Internals2/opcodes/isset-isempty-var-Phpdoc专题
ISSET_ISEMPTY_VAR
PHP code
<?php
/*
* Tests if the value of a variable is set or not.
* opcode number: 114
*/
if(isset($a)){ return 0;}
?>PHP opcodes
Function name: (null)
Compiled variables: !0=$a
| line | # | op | fetch | ext | return | operands |
|---|---|---|---|---|---|---|
| 6 | 0 | ZEND_ISSET_ISEMPTY_VAR | 5 | ~0 | !0 | |
| 1 | JMPZ | ~0,->4 | ||||
| 2 | RETURN | 0 | ||||
| 3 | JMP | ->4 | ||||
| 7 | 4 | RETURN | 1 |