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phpinteger-overflow

Minimum integer in PHP 7

In interactive mode on PHP 7 (64 bit Ubuntu),

php > echo true;
1
php > echo false; # no output for false
php > echo PHP_INT_MIN == -9223372036854775808;
1
php > echo is_int(PHP_INT_MIN);
1
php > echo is_int(-9223372036854775808);

Why doesn't the last line output 1?

Solution

  • var_dump() is your friend.

    var_dump(
    PHP_INT_MIN,
    is_int(PHP_INT_MIN),
    -9223372036854775808,
    is_int(-9223372036854775808)
);

/* Output:
int(-9223372036854775808)
bool(true)
float(-9.2233720368548E+18)
bool(false)
*/