var_dump() is debugging functionality, so it should print
floating-point numbers accurately. We do this by switching
to serialize_precision, which (by default) will print with
as much precision as necessary to preserve the exact value
of the float.
This also affects debug_zval_dump().
Closes GH-5172.
The fdiv() function is part of the fmod() / intdiv() family. It
implements a floating-point division with IEEE-754 semantics.
That is, division by zero is considered well-defined and does not
trigger any kind of diagnostic. Instead one of INF, -INF or NAN
will be returned, depending on the case.
This is in preparation for throwing DivisionByZeroError from the
standard division operator.
Nikita Popov