eregi for alpha-numeric, punctuation & whitespace?

Not sure how to accomplish this, and not completely familiar with all the options available with regular expressions. I need to sanitize input data by only allowing alpha-numeric characters, whitespace, punctuation (,.;:) and of course carrige returns. here is what I have so far... eregi("^[0-9a-zA-Z]{1,40}$",$_POST['input']) Any help is appreciated, right now anything with a space, period, comma etc gets flagged. Jas