Implementation:ClickHouse ClickHouse ArithmeticOverflow

Knowledge Sources	ClickHouse
Domains	Arithmetic, Safety
Last Updated	2026-02-08 00:00 GMT

Overview

Safe arithmetic operations that detect and handle integer overflow using compiler builtins.

Description

Provides overflow-safe arithmetic functions using GCC/Clang builtins like `__builtin_add_overflow`. Supports addition, subtraction, and multiplication for all integer types including 128 and 256-bit integers.

Usage

Use when performing arithmetic that might overflow, implementing safe numeric operations, or validating computation results.

Code Reference

Source Location

• Repository: ClickHouse
• File: base/base/arithmeticOverflow.h
• Lines: 1-211

Signature

template <typename T>
bool addOverflow(T x, T y, T & res);

template <typename T>
bool subOverflow(T x, T y, T & res);

template <typename T>
bool mulOverflow(T x, T y, T & res);

template <typename T1, typename T2>
auto mulIgnoreOverflow(T1 x, T2 y);
template <typename T1, typename T2>
auto addIgnoreOverflow(T1 x, T2 y);
template <typename T1, typename T2>
auto subIgnoreOverflow(T1 x, T2 y);

Import

#include <base/arithmeticOverflow.h>

Usage Examples

#include <base/arithmeticOverflow.h>

Int64 result;
if (common::addOverflow(INT64_MAX, 1LL, result)) {
    // Overflow occurred
} else {
    // result contains sum
}

// Multiply with overflow check
UInt64 product;
if (common::mulOverflow(1000000ULL, 1000000ULL, product)) {
    // Overflow
}

// Ignore overflow (for cases where wrapping is acceptable)
auto sum = common::addIgnoreOverflow(INT32_MAX, 1);

Related Pages

• Principle:ClickHouse_ClickHouse_Overflow_Safe_Arithmetic