Standard library header <charconv> (C++17)

 

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Standard library headers

Language support <cfloat> <climits> <compare> (C++20) <coroutine> (C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint> (C++11) <cstdlib> <exception> <initializer_list> (C++11)    <limits> <new> <source_location> (C++20) <stdfloat> (C++23) <typeinfo> <version> (C++20) Concepts <concepts> (C++20) Diagnostics <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) Memory management <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) Metaprogramming <type_traits> (C++11) <ratio> (C++11)

General utilities <any> (C++17) <bitset> <bit> (C++20) <charconv> (C++17) <expected> (C++23) <format> (C++20) <functional> <optional> (C++17) <tuple> (C++11) <typeindex> (C++11) <utility> <variant> (C++17) Containers <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <inplace_vector> (C++26)    <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> Iterators <iterator> Ranges <generator> (C++23) <ranges> (C++20)

Algorithms <algorithm> <numeric> Strings <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> Text processing <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)    Numerics <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <valarray> Time <chrono> (C++11) <ctime> C compatibility <ccomplex> (C++11/17/20*) <ciso646> (until C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

Input/output <cinttypes> (C++11) <cstdio> <filesystem> (C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print> (C++23) <spanstream> (C++23) <sstream> <streambuf> <strstream> (C++98/26*) <syncstream> (C++20) Concurrency support <atomic> (C++11) <barrier> (C++20) <condition_variable> (C++11) <future> (C++11) <hazard_pointer> (C++26) <latch> (C++20) <mutex> (C++11) <rcu> (C++26) <semaphore> (C++20) <shared_mutex> (C++14) <stdatomic.h> (C++23) <stop_token> (C++20) <thread> (C++11) Execution support <execution> (C++17)

 

This header is part of the strings library.

Classes
chars_format (C++17)	specifies formatting for std::to_chars and std::from_chars (enum)
from_chars_result (C++17)	the return type of std::from_chars (class)
to_chars_result (C++17)	the return type of std::to_chars (class)
Functions
from_chars (C++17)	converts a character sequence to an integer or floating-point value (function)
to_chars (C++17)	converts an integer or floating-point value to a character sequence (function)

Synopsis

namespace std {
  // floating-point format for primitive numerical conversion
  enum class chars_format {
    scientific = /* unspecified */,
    fixed = /* unspecified */,
    hex = /* unspecified */,
    general = fixed | scientific
  };
 
 
  // primitive numerical output conversion
  struct to_chars_result { // freestanding
    char* ptr;
    errc ec;
    friend bool operator==(const to_chars_result&, const to_chars_result&) = default;
    constexpr explicit operator bool() const noexcept { return ec == errc{}; }
  };
 
  constexpr
  to_chars_result to_chars(char* first, char* last, // freestanding
                           /* integer-type */ value, int base = 10);
  to_chars_result to_chars(char* first, char* last, // freestanding
                           bool value, int base = 10) = delete;
  to_chars_result to_chars(char* first, char* last, // freestanding-deleted
                           /* floating-point-type */ value);
  to_chars_result to_chars(char* first, char* last, // freestanding-deleted
                           /* floating-point-type */ value, chars_format fmt);
  to_chars_result to_chars(char* first, char* last, // freestanding-deleted
                           /* floating-point-type */ value,
                           chars_format fmt, int precision);
 
  // primitive numerical input conversion
  struct from_chars_result { // freestanding
    const char* ptr;
    errc ec;
    friend bool operator==(const from_chars_result&, const from_chars_result&) = default;
    constexpr explicit operator bool() const noexcept { return ec == errc{}; }
  };
 
  constexpr
  from_chars_result from_chars(const char* first, // freestanding
                               const char* last, /* integer-type */& value,
                               int base = 10);
  from_chars_result from_chars(const char* first, // freestanding-deleted
                               const char* last, /* floating-point-type */& value,
                               chars_format fmt = chars_format::general);
}