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    func_num_args

    (PHP 4, PHP 5, PHP 7, PHP 8)

    func_num_args — 関数に渡された引数の数を返す

    説明

    func_num_args(): int

    関数に渡された引数の数を取得します。

    この関数は func_get_arg() および func_get_args() と組み合わせて使用され、 ユーザー定義関数において可変長の引数リストを使用することができるようになります。

    パラメータ

    この関数にはパラメータはありません。

    戻り値

    現在のユーザー定義関数に渡された引数の数を返します。

    エラー / 例外

    ユーザー定義関数の外部からコールされた場合に警告を発生します。

    例

    例1 func_num_args() の例

    <?php
    function foo()
    {
    echo     "引数の数: ", func_num_args(), PHP_EOL;
    }

    foo(1, 2, 3);
    ?>

    上の例の出力は以下となります。

    引数の数: 3

    注意

    注意:

    PHP 8.0.0 以降における func_*() 関数ファミリは、名前付き引数に関しては、ほぼ透過的に動作するはずです。つまり、渡された全ての引数は位置を指定したかのように扱われ、引数が指定されない場合は、デフォルト値で置き換えられるということです。 この関数は、未知の名前付きの可変長引数を無視します。 未知の名前付き引数は、可変長引数を通じてのみアクセスできます。

    参考

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    User Contributed Notes 6 notes

    up
    39
    jared at ws-db dot com
    19 years ago
    Just a note for anyone wondering. This function doesn't include params that have a default value, unless you pass one in to overwrite the default param value. Not sure if that makes sense, so here's an example:

    <?php
    function helloWorld($ArgA, $ArgB="HelloWorld!") {
    return     func_num_args();
    }

    // The following will return 1
    $Returns1 = helloWorld("HelloWorld!");

    // The following will return 2
    $Returns2 = helloWorld("HelloWorld!", "HowdyWorld!");
    ?>
    up
    9
    Dennis Robinson from basnetworks dot net
    15 years ago
    This function comes in handy, and I believe is the only solution, when you have an optional parameter that can take any type of data.

    For example:

    <?php

    // $data can be of any type, including null
    function my_function($name, $data = null)
    {
    if (    $data !== null)
    {
    // Do something with $data
    // If you call my_function('something'), this WILL NOT be reached
    // If you call my_function('something', null), this WILL NOT be reached
    }
    }

    ?>

    The problem with the above function is that you will never be able to use null as the value for $data. To fix this, use func_num_args() like so:

    <?php

    // $data can be of any type, including null
    function my_function($name, $data = null)
    {
    if (    func_num_args() >= 2)
    {
    // Do something with $data
    // If you call my_function('something'), this WILL NOT be reached
    // If you call my_function('something', null), this WILL be reached
    }
    }

    ?>

    This solution works because func_num_args() reports exactly how many arguments were passed when the function was called. It does not take into account when default argument values are used.
    up
    1
    tongcheong77 at gmail dot com
    7 years ago
    If you are using PHP 7 and func_num_args is in your base class which you extended, you can pass your arguments with the 'spat' operator.

    class Sql {

    public function doGetWhere(...$args) {

    $num_args = func_num_args();
    $args_list = func_get_args();

    echo '<pre>';
    var_dump($args_list);
    echo '<pre>';
    }
    }

    class Member extends Sql {

    public function getWhere(...$args) {

    $this->doGetWhere(...$args);

    }
    }

    $member = new Member();
    $member->getWhere('first_name','last_name','userlevel','email','where','email','=',$sub_email);

    However, take note that if you 'new up' the 'Sql' class in your 'Member' class above, instead of extending it, you will not need to pass your arguments as a variable. Just my two cents. -Bruce tong
    up
    3
    luisguillermo dot quevedovelez at gmail dot com
    12 years ago
    I had defined a function function_name(){ ...} as a drupal callback.
    I try to get how many params where passed

    I got a Error and my Site falls down

    I've replaced func_get_args() instead func_num_args() and my Site was restored.

    I conclude you can not use func_num_args() in callbacks.

    Hope it helps.
    up
    2
    thalis at NOSPAMcs dot pitt dot edu
    22 years ago
    The idea of func_get_args() is to construct functions of variable number of parameters like

    <?php
    function var_param_func(){
    if(    func_num_args()==0){
    //do one thing
    }
    if(    func_num_args()==1)
    //do another thing
    //get the args with func_get_args()
    }
    }
    ?>
    up
    0
    ashley at dcs dot warwick dot ac dot uk
    22 years ago
    If you want to pass the parameters on intact to another function, use func_get_args and call_user_func_array (careful - this one is only available in recent PHP versions). For example:

    <?php
    /* Print an HTML tag. This accepts a variable number of arguments:
    the first should be the name of the tag, followed by pairs of
    arguments that describe keys and values. The values are printed
    with surrounding double quote characters. */
    function printTag() {
    $numArgs = func_num_args();
    if (    $numArgs < 1) die("printTag given no arguments");

    echo     "<" . func_get_arg(0);
    for (    $i = 1; $i < $numArgs; $i+=2) {
    echo     " " . func_get_arg($i);
    if (    $i+1 < $numArgs)
    echo     "=\"" . func_get_arg($i+1) . "\"";
    }
    echo     ">";

    }

    /* Print an HTML tag with a newline on the end */
    function printTagNL() {
    $args = func_get_args();
    call_user_func_array("printTag", $args);
    echo     "\n";
    }

    printTagNL("input", "type", "hidden", "name", "SORTORDER", "value", $columnNo);
    ?>
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