gistfile1.php

<?php

# PHP does not recognize long int.
# It recognize only signed int32.

var_dump(is_float(pow(2,30)));  # false
var_dump(is_float(pow(2,31)));  # true (sic!)

# Even if PHP keep long int internaly as floats,
# it displays them in inconsistent way:

print pow(2,31)."\n"; # 2147483648
var_dump(pow(2,31));

print pow(2,39)."\n"; # 549755813888 ... WTF?
var_dump(pow(2,39));  # float(549755813888)

print pow(2,40)."\n"; # 1.09951162778E+12
var_dump(pow(2,40)); # float(1.09951162778E+12)

# But do really floats are always floats? It depends :P

var_dump(-2147483648); # float(-2147483648) 

# but

var_dump(-2147483647 - 1);  # int(-2147483648)
var_dump(-PHP_INT_MAX -1);  # int(-2147483648)

# so THE SAME number may be int or float. If it is not schizofrenic,
# it is maybe php fuzzy logic :P

?>