PHP is_nan() Function

The is_nan() function checks whether a value is 'not a number'.

This function returns true (1) if the specified value is 'not a number', otherwise it returns false/nothing.

bool is_nan ( mixed $val )

Checks whether val is 'not a number', like the result of acos(1.01).

Example -

ParameterDescription
valThe value to check

Return Values

Returns TRUE if val is 'not a number', else FALSE.