---
name: "ckd_add"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/ckd_add"
---

# ckd\_add(3)

checked integer arithmetic

## NAME

**stdckdint** – checked integer arithmetic

## SYNOPSIS

**#include \<stdckdint.h\>**

*bool*\

**ckd\_add**(*type1 \*result*, *type2 a*, *type3 b*);

*bool*\

**ckd\_sub**(*type1 \*result*, *type2 a*, *type3 b*);

*bool*\

**ckd\_mul**(*type1 \*result*, *type2 a*, *type3 b*);

## DESCRIPTION

The function-like macros **ckd\_add**, **ckd\_sub**, and **ckd\_mul** perform checked integer addition, subtraction, and multiplication, respectively. If the result of adding, subtracting, or multiplying *a* and *b* as if their respective types had infinite range fits in *type1*, it is stored in the location pointed to by *result* and the macro evaluates to false. Otherwise, the macro evaluates to true and the contents of the location pointed to by *result* is the result of the operation wrapped to the range of *type1*.

## RETURN VALUES

The **ckd\_add**, **ckd\_sub**, and **ckd\_mul** macros evaluate to true if the requested operation overflowed the result type and false otherwise.

## EXAMPLES

```
#include <assert.h>
#include <limits.h>
#include <stdckdint.h>
int main(void)
{
	int result;
	assert(!ckd_add(&result, INT_MAX, 0));
	assert(result == INT_MAX);
	assert(ckd_add(&result, INT_MAX, 1));
	assert(result == INT_MIN);
	assert(!ckd_sub(&result, INT_MIN, 0));
	assert(result == INT_MIN);
	assert(ckd_sub(&result, INT_MIN, 1));
	assert(result == INT_MAX);
	assert(!ckd_mul(&result, INT_MAX / 2, 2));
	assert(result == INT_MAX - 1);
	assert(ckd_mul(&result, INT_MAX / 2 + 1, 2));
	assert(result == INT_MIN);
	return 0;
}
```

## HISTORY

The **ckd\_add**, **ckd\_sub**, and **ckd\_mul** macros were first introduced in FreeBSD 14.0.

## AUTHORS

The **ckd\_add**, **ckd\_sub**, and **ckd\_mul** macros and this manual page were written by Dag-Erling Smørgrav ⟨*des@FreeBSD.org*⟩.