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.
The argument offset. Function arguments are counted starting from zero.
Returns the specified argument, or FALSE
on error.
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.
This function can now be used in parameter lists.
If 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
.
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.
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.
<?php function 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
test.php <?php function 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
<?php function 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'
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