fixed_string

C++ library that provides a basic_fixed_string template combining std::array's fixed-size semantics with std::string semantics.

Features

• C++17 or higher
• Header-only
• Dependency-free
• No dynamic allocations
• Fully constexpr
• Can be used as a class non-type template parameter (since C++20)

Examples

• Construction

constexpr fixstr::fixed_string foo = "foo";

• Concatenation

using namespace fixstr;
constexpr fixed_string first = "Hello, ";
constexpr fixed_string second = "World!";
constexpr auto result = first + second; // "Hello, World!"

• Comparison

using namespace fixstr;
constexpr fixed_string first = "Hello, ";
constexpr fixed_string second = "World!";
static_assert(first == second); // false
static_assert(first != second); // true
static_assert(first < second);  // true
static_assert(first <= second); // true
static_assert(first > second);  // false 
static_assert(first >= second); // false
static_assert(first <=> second != 0); // true

• Non-type template parameter

template <fixstr::fixed_string Foo>
void bar()
{
    static_assert(Foo == "foo"sv);
}

void foo()
{
    bar<"foo">();
}

Integration

Since it's a header-only library, you just need to copy fixed_string.hpp to your project.

If you are using vcpkg for external dependencies, you can use the fixed-string package.

If you are using Conan for external dependencies, you can use the Conan recipe located in the root of the repository.

Compiler compatibility

• GCC >= 7.3
• Clang >= 5
• ICC >= 19.0.1
• MSVC >= 14.28 / Visual Studio 2019 (I don't have access to older versions, so it might work on them too)

Using basic_fixed_string as a class non-type template parameter is fully available in GCC >= 10 and VS 2019 16.9 or newer