# <stdckdint.h>

**[<stdckdint.h>](https://en.cppreference.com/w/c/header/stdckdint)** provides checked arithmetic macros (C23): `ckd_add`, `ckd_sub`, `ckd_mul`. They perform the operation and return `true` if overflow occurred, `false` otherwise, without triggering undefined behavior.

Use these instead of manual overflow checks for cleaner, safer code.

## Example

This example demonstrates overflow detection for addition and multiplication.

```c
// compile: gcc -std=c2x -o stdckdintexample stdckdintexample.c
// run: ./stdckdintexample
// description: checked arithmetic detecting overflow

#include <stdckdint.h>
#include <limits.h>
#include <stdio.h>

int main() {
    int result;
    
    if (ckd_add(&result, INT_MAX, 1)) {
        printf("INT_MAX + 1 overflows\n");
    }
    
    long product;
    if (ckd_mul(&product, 1000000L, 1000000L)) {
        printf("1000000 * 1000000 overflows long\n");
    } else {
        printf("product = %ld\n", product);
    }
    
    return 0;
}
```

## Common macros

**Checked arithmetic** (return true on overflow, result stored in first arg):
- `ckd_add(result_ptr, a, b)`: checked addition
- `ckd_sub(result_ptr, a, b)`: checked subtraction
- `ckd_mul(result_ptr, a, b)`: checked multiplication

All three macros:
- Store the result (if no overflow) at `result_ptr`
- Return non-zero (true) if overflow occurred
- Return 0 (false) if no overflow
- Never trigger undefined behavior even on overflow