PHP Manual . Prev . Next . ... User-defined functions . Function arguments . ... In PHP 3, functions must be defined before they are referenced. ... PHP 3 does not support variable numbers of arguments to functions, although default arguments are supported (see Default argument values for more information). PHP 4 supports both: see Variable-length argument lists and the function references for func_num_args() , func_get_arg() , and func_get_args() for more information. ...