NAME¶

std::to_chars_result - std::to_chars_result

Synopsis¶

Defined in header <charconv>
struct to_chars_result; (since C++17)

std::to_chars_result is the return type of std::to_chars. It has no base classes,
and only has the following members.

Notes¶

Feature-test macro Value Std Feature
201611L (C++17) Elementary string conversions (std::to_chars,
__cpp_lib_to_chars std::from_chars)
202306L (C++26) Testing for success or failure of <charconv>
functions

Example¶

// Run this code

#include <array>
#include <charconv>
#include <iostream>
#include <string_view>
#include <system_error>

void show_to_chars(auto... format_args)
{
std::array<char, 10> str;

#if __cpp_lib_to_chars >= 202306L
// use C++26 operator bool() for error checking
if (auto res = std::to_chars(str.data(), str.data() + str.size(), format_args...))
std::cout << std::string_view(str.data(), res.ptr) << '\n';
else
std::cout << std::make_error_code(res.ec).message() << '\n';
#else
if (auto [ptr, ec]
= std::to_chars(str.data(), str.data() + str.size(), format_args...);
ec == std::errc())
std::cout << std::string_view(str.data(), ptr) << '\n';
else
std::cout << std::make_error_code(ec).message() << '\n';
#endif
}

int main()
{
show_to_chars(42);
show_to_chars(+3.14159F);
show_to_chars(-3.14159, std::chars_format::fixed);
show_to_chars(-3.14159, std::chars_format::scientific, 3);
show_to_chars(3.1415926535, std::chars_format::fixed, 10);
}

Possible output:¶

42
3.14159
-3.14159
-3.142e+00
Value too large for defined data type

See also¶

to_chars converts an integer or floating-point value to a character sequence
(C++17) (function)