No, no function provides the automatic cast. However you can cast with this simple hack (the cast is automatically made by PHP in internal):

float = "1.23"+0;

for generic number:

$yourNumberCasted = $yourStringNumber + 0;

With a function:

function castToNumber($genericStringNumber) { 
    return $genericStringNumber+0; 
}
$yourNumberCasted = castToNumber($yourStringNumber);

This might do the trick for you

string serialcomnum = Regex.Match(serialcom,"\\d+").ToString();
int ints = Convert.ToInt32(serialcomnum);

Another way could be

string serialcom = "$67%!$127a%";
var serialcomnum = Regex.Replace(serialcom, @"[^0-9]+", ",");
serialcomnum = serialcomnum.TrimStart(',').TrimEnd(',');
int[] serialints = serialcomnum.Split(',').Select(int.Parse).ToArray();

You can use the strval() function to convert a number to a string.

From a maintenance perspective its obvious what you are trying to do rather than some of the other more esoteric answers. Of course, it depends on your context.

$var = 5;

// Inline variable parsing
echo "I'd like {$var} waffles"; // = I'd like 5 waffles

// String concatenation 
echo "I'd like ".$var." waffles"; // I'd like 5 waffles

// The two examples above have the same end value...
// ... And so do the two below

// Explicit cast 
$items = (string)$var; // $items === "5";

// Function call
$items = strval($var); // $items === "5";

After doing a fair bit of digging, there is no solution to this in Hacklang at the moment. The only thing you have is \Stringish, an undocumented interface that covers both native strings and objects with the __toString method. It does not, however, cover int, float or bool.

Source: interfaces.hhi

You can use sprintf to do it, or maybe snprintf if you have it:

char str[ENOUGH];
sprintf(str, "%d", 42);

Where the number of characters (plus terminating char) in the str can be calculated using:

(int)((ceil(log10(num))+1)*sizeof(char))