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std::sub_sat(3) C++ Standard Libary std::sub_sat(3) NAME std::sub_sat - std::sub_sat Synopsis Defined in header <numeric> template< class T > (since C++26) constexpr T sub_sat( T x, T y ) noexcept; Computes the saturating subtraction x - y. This operation (unlike built-in arithmetic operations on integers) behaves as-if it is a mathemati- cal operation with an infinite range. Let q denote the result of such operation. Re- turns: * q, if q is representable as a value of type T. Otherwise, * the largest or smallest value of type T, whichever is closer to the q. This overload participates in overload resolution only if T is an integer type, that is: signed char, short, int, long, long long, an extended signed in- teger type, or an unsigned version of such types. In particular, T must not be (possi- bly cv-qualified) bool, char, wchar_t, char8_t, char16_t, and char32_t, as these types are not intended for arithmetic. Parameters x, y - integer values Return value Saturated x - y. Exceptions Throws no exceptions. Notes Unlike the built-in arithmetic operators on integers, the integral promotion does not apply to the x and y arguments. If two arguments of different type are passed, the call fails to compile, i.e. the behavior relative to template argument deduction is the same as for std::min or std::max. Most modern hardware architectures have efficient support for satu- ration arithmetic on SIMD vectors, including SSE2 for x86 and NEON for ARM. Feature-test macro Value Std Feature __cpp_lib_saturation_arithmetic 202311L (C++26) Saturation arith- metic Possible implementation See libstdc++ (gcc). Example Can be previewed on Compiler Explorer // Run this code #include <climits> #include <numeric> static_assert ("" && (std::sub_sat<int>(INT_MIN + 4, 3) == INT_MIN + 1) // not satu- rated && (std::sub_sat<int>(INT_MIN + 4, 5) == INT_MIN) // saturated && (std::sub_sat<int>(INT_MAX - 4, -3) == INT_MAX - 1) // not sat- urated && (std::sub_sat<int>(INT_MAX - 4, -5) == INT_MAX) // saturated && (std::sub_sat<unsigned>(4, 3) == 1) // not saturated && (std::sub_sat<unsigned>(4, 5) == 0) // saturated ); int main() {} See also add_sat saturating addition operation on two integers (C++26) (function template) mul_sat saturating multiplication operation on two integers (C++26) (function template) div_sat saturating division operation on two integers (C++26) (function template) saturate_cast returns an integer value clamped to the range of a an- other integer (C++26) type (function template) clamp clamps a value between a pair of boundary values (C++17) (function template) in_range checks if an integer value is in the range of a given integer type (C++20) (function template) min returns the smallest finite value of the given type [static] (public static member function of std::numeric_lim- its<T>) max returns the largest finite value of the given type [static] (public static member function of std::numeric_lim- its<T>) External links 1. A branch-free implementation of saturation arithmetic Lockless- inc.com, 2012 http://cppreference.com 2024.06.10 std::sub_sat(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Notes | Possible implementation | Example | See also | External links
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