PHP函数库分类二十八.doc

PHP函数库分类二十八 9.Function Handing 函数列表2 ? func_get_arg?- Return an item from the argument list func_get_arg (PHP 4, PHP 5) func_get_arg?—?Return an item from the argument list 说明 mixed?func_get_arg?(?int?$arg_num?) Gets the specified argument from a user-defined functions argument list. This function may be used in conjunction with?func_get_args()?and func_num_args()?to allow user-defined functions to accept variable-length argument lists. 参数 arg_num The argument offset. Function arguments are counted starting from zero. 返回值 Returns the specified argument, or?FALSE?on error. 更新日志 版本说明5.3.0This function can now be used in parameter lists.5.3.0If this function is called from the outermost scope of a file which has been included by calling?include()?or?require()?from within a function in the calling file, it now generates a warning and returns?FALSE.错误/异常 Generates a warning if called from outside of a user-defined function, or ifarg_num?is greater than the number of arguments actually passed. 范例 Example #1?func_get_arg()?example ?phpfunction?foo(){?????$numargs?=?func_num_args();?????echo?Number?of?arguments:?$numargsbr?/ ;?????if?($numargs?=?2)?{?????????echo?Second?argument?is:??.?func_get_arg(1)?.?br?/ ;?????}}foo?(1,?2,?3);? Example #2?func_get_arg()?example before and after PHP 5.3 test.php?phpfunction?foo()?{????include?./fga.inc;}foo(First?arg,?Second?arg);?fga.php?php$arg?=?func_get_arg(1);var_export($arg);? Output previous to PHP 5.3: Second arg Output in PHP 5.3 and later: Warning: func_get_arg(): Called from the global scope - no function context in /home/torben/Desktop/code/ml/fga.inc on line 3 false Example #3?func_get_arg()?example of byref and byval arguments ?phpfunction?byVal($arg)?{????echo?As?passed?????:?,?var_export(func_get_arg(0)),?PHP_EOL;????$arg?=?baz;????echo?After?change??:?,?var_export(func_get_arg(0)),?PHP_EOL;}function?byRef($arg)?{????echo?As?passed?????:?,?var_export(func_get_arg(0)),?PHP_EOL;