---
description: "Learn more about: Arithmetic overflow: '%operator%' operation causes overflow at compile time. Use a wider type to store the operands"
title: C26450
keywords: C26450
ms.date: 01/08/2017
ms.topic: "reference"
f1_keywords: ["C26450"]
helpviewer_keywords: ["C26450"]
dev_langs: ["C++"]
---
# Arithmetic overflow: '%operator%' operation causes overflow at compile time. Use a wider type to store the operands

This warning indicates that an arithmetic operation was provably lossy at compile time. This can be asserted when the operands are all compile-time constants.  Currently, we check left shift, multiplication, addition, and subtraction operations for such overflows.

Note: C4307 is a similar check in the Microsoft C++ compiler.

## Example 1

```cpp
int multiply()
{
    const int a = INT_MAX;
    const int b = 2;
    int c = a * b; // C26450 reported here
    return c;
}
```

To correct this warning, use the following code.

```cpp
long long multiply()
{
    const int a = INT_MAX;
    const int b = 2;
    long long c = (long long)a * b; // OK
    return c;
}
```

## Example 2

```cpp
int add()
{
    const int a = INT_MAX;
    const int b = 2;
    int c = a + b; // C26450 reported here
    return c;
}
```

To correct this warning, use the following code:

```cpp
long long add()
{
    const int a = INT_MAX;
    const int b = 2;
    long long c = (long long)a + b; // OK
    return c;
}
```

## Example 3

```cpp
int subtract()
{
    const int a = -INT_MAX;
    const int b = 2;
    int c = a - b; // C26450 reported here
    return c;
}
```

To correct this warning, use the following code.

```cpp
long long subtract()
{
    const int a = -INT_MAX;
    const int b = 2;
    long long c = (long long)a - b; // OK
    return c;
}
```

## See also

[ES.103: Don't overflow](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Res-overflow)