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int_mul_add_overflow

Note

This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.

Returns the overflow part of multiplying two ints plus another int, as if they were all unsigned

namespace HH;

function int_mul_add_overflow(
  int $a,
  int $b,
  int $bias,
): int;

Specifically, this returns the upper 64 bits of full (unsigned)$a * (unsigned)$b + (unsigned)$bias. $bias can be used to manipulate rounding of the result.

Parameters​

  • int $a
  • int $b
  • int $bias

Returns​

  • int