PHP func_get_args function

The func_get_args function returns, as an array, the arguments that have been passed to the function containing the call. This allows you to simplify the previous code to use a foreach loop:

$arglist = func_get_args();
foreach ($arglist as $arg) {
  // process $arg
}

Like the other argument processing functions, it will generate a warning when not called from inside a function.

PHP func_get_arg function

The func_get_arg, when passed an integer, will return the argument passed to the current function, indexed by that integer. To process a variable argument list, you could use code such as:

for ($index = 0; index < func_num_args(); index++) {
   $arg = func_get_arg(index);
}

The limitation of this function is that it does not take into account the default arguments when a value has not been passed by the call to the function.

PHP func_num_args function

The func_num_args function returns the number of arguments that were passed to a function and must be called from within that function. For example:

function variable_argument_function () {
  $num_args = func_num_args();
  echo ("I was passed $num_args arguments.");
}
variable_argument_function ("w3m", 1, 2,2);

The output from this code snippet will be:

I was passed 4 arguments.

PHP function_exists function

The function_exists function tests to see whether a specific named function has been defined and implemented in the current scope. It is useful for testing, given a possible collection of equivalent routines, which is available for use or for making sure that the function that is about to be defined does not use a name that is already taken.

PHP getdate function

The getdate function returns an array that contains several key/ value pairs, representing the current date/time at the server:

mday From 1 to 31 (day of the month)
wday From 0 to 6 (Sunday to Saturday)
mon Numeric month of year, 1 to 12
month Textual equivalent of mon, January to December
year The year, in four-digit format; that is, 2008
yday The day of the year, zero-based
hours The hour component of the current time, 0 to 23
minutes The minute component of the current time, 0 to 59
seconds The second component of the current time, 0 to 59

Each of these key/value pairs can be accessed through its key:

$today_date = getdate();
echo "The month is $today_date['month'].";

PHP die function

The die function is used to do two things:
* Print an error message
* Halt the script

When die is encountered, no more processing will take place, and the error message passed to the function (if any) will be displayed. An example is as follows:

if (not_logged_in($user)) {
   die ("Error : $user not logged in.");
}

die is generally used to catch system errors such as the inability to connect to a database.

PHP eval function

The eval function takes a string and evaluates it is if it were PHP code:

eval("$my_var = "a site");
echo $my_var;

This code will output “a site”. The $my_var variable had not existed until the eval function was called. The return value from eval is always set to null unless the code in the evaluation part returns a value, in which case the return value is passed back as the eval return value.