ckd_add - cppreference.com (original) (raw)

| | | | | ----------------------------------------------------------------------------------------------------- | | ------------- | | template< class type1, class type2, class type3 > bool ckd_add( type1* result, type2 a, type3 b ); | | (since C++26) |

Computes the addition x + y and stores the result into *result. The addition is performed as if both operands were represented in a signed integer type with infinite range, and the result was then converted from this integer type to type1. If the value assigned to *result correctly represents the mathematical result of the operation, it returns false. Otherwise, it returns true. In this case, the value assigned to *result is the mathematical result of the operation wrapped around to the width of *result.

[edit] Parameters

a, b - integer values
result - address of where result should be stored

[edit] Return value

false if the value assigned to *result correctly represents the mathematical result of the addition, true otherwise.

[edit] Note

The function template ckd_add has the same semantics as the corresponding type-generic macro with the same name specified in C23.

Each of the types type1, type2, and type3 is a cv-unqualified signed or unsigned integer type.

It is recommended to produce a diagnostic message if type2 or type3 are not suitable integer types, or if *result is not a modifiable lvalue of a suitable integer type.

[edit] Example

Compiler Explorer preview.

#include #include #include #include <stdckdint.h>   int main() { const std::uint8_t x{14}; std::uint16_t y{28}, result1{}; bool overflow{};   overflow = ckd_add(&result1, x, y); std::println("{} + {} => {} ({})", x, y, result1, overflow ? "Overflow" : "OK");   y = std::numeric_limits<std::uint16_t>::max(); overflow = ckd_add(&result1, x, y); std::println("{} + {} => {} ({})", x, y, result1, overflow ? "Overflow" : "OK");   std::uint32_t result2{}; overflow = ckd_add(&result2, x, y); std::println("{} + {} => {} ({})", x, y, result2, overflow ? "Overflow" : "OK"); }

Possible output:

14 + 28 => 42 (OK) 14 + 65535 => 13 (Overflow) 14 + 65535 => 65549 (OK)

[edit] References

[edit] See also

| | checked subtraction operation on two integers (function template) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | checked multiplication operation on two integers (function template) [edit] | | |