Php/docs/function.func-get-arg
func_get_arg
(PHP 4, PHP 5, PHP 7)
func_get_arg — Return an item from the argument list
Description
func_get_arg
( int $arg_num
) : mixed
Gets the specified argument from a user-defined function's 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.
Parameters
arg_num- The argument offset. Function arguments are counted starting from zero.
Return Values
Returns the specified argument, or FALSE on error.
Errors/Exceptions
Generates a warning if called from outside of a user-defined function, or
if arg_num is greater than the number of arguments
actually passed.
Examples
Example #1 func_get_arg() example
<?phpfunction foo(){ $numargs = func_num_args(); echo "Number of arguments: $numargs\n"; if ($numargs >= 2) { echo "Second argument is: " . func_get_arg(1) . "\n"; }}foo(1, 2, 3);?>
The above example will output:
Number of arguments: 3 Second argument is: 2
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.inc<?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; $arg = 'baz'; echo 'After change : ', var_export(func_get_arg(0)), PHP_EOL;}$arg = 'bar';byVal($arg);byRef($arg);?>
Output of the above example in PHP 7:
As passed : 'bar' After change : 'baz' As passed : 'bar' After change : 'baz'
Output of the above example in PHP 5:
As passed : 'bar' After change : 'bar' As passed : 'bar' After change : 'baz'
Notes
Note:
Because this function depends on the current scope to determine parameter details, it cannot be used as a function parameter in versions prior to 5.3.0. If this value must be passed, the results should be assigned to a variable, and that variable should be passed.
Note:
If the arguments are passed by reference, any changes to the arguments will be reflected in the values returned by this function. As of PHP 7 the current values will also be returned if the arguments are passed by value.
Note:
This function returns a copy of the passed arguments only, and does not account for default (non-passed) arguments.
