Description:
------------
The problem is known, but the result can't be the last answer.
I must calculate the body mass index for my company.
Yesterday I registered rounding errors between 0.1 and 0.3.
The problem: german doctors declares weight as "63,3" and not as "63.3".
It was my fault trusting in PHPs typecasting.
BUT: why trying typecasting a stupid string, so round() gives a "correct" answer?
I except returning FALSE, if the given parameter contains something else than "0-9" and ".".

Reproduce code:
---------------
$var = "German doctors don't know the point.";
print round($var, 1);
$var = "3 german doctors dont't know the point.";
print round($var, 1);
$var = "3,467";
print round($var, 1);
$var = "3.465";
print round($var, 1);

Expected result:
----------------
FALSE
FALSE
FALSE
3,5

Actual result:
--------------
0
3
3
3.5