PHP: func_num_args

Description

int func_num_args ( void )

Returns the number of arguments passed into the current user-defined function. func_num_args() will generate a warning if called from outside of a user-defined function. This function cannot be used directly as a function parameter. Instead, its result may be assigned to a variable, which can then be passed to the function.


<?php

function foo() 

{

    $numargs = func_num_args();

    echo "Number of arguments: $numargs\n";

} 



foo(1, 2, 3);    // Prints 'Number of arguments: 3'

?>

func_num_args() may be used in conjunction with func_get_arg() and func_get_args() to allow user-defined functions to accept variable-length argument lists.

User Contributed Notes
func_num_args

andy at arakka dot co dot th
11-May-2005 09:16


func_num_args() can be used in conjunction with named arguments, also. For example:

function DebugShow( $label, $value ) {

  echo "# " . $label ;

  if ( func_num_args() > 1 ) echo " = " . $value ;

  echo "<br>";

}

ashley at dcs dot warwick dot ac dot uk
17-Apr-2002 06:40


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:



/* 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);

thalis at NOSPAMcs dot pitt dot edu
29-Mar-2002 02:05


The idea of func_get_args() is to construct functions of variable number of parameters like

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()

    }

}