Standard library header <charconv>

 

C++

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Technical Specifications

 

Standard Library headers

Language Support
<cstddef> <cstdlib> <version> <limits> <climits>	<cfloat> <cstdint> <new> <typeinfo>	<source_location> <exception> <initializer_list> <compare>	<coroutine> <csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator>	<bitset> <tuple> <optional> <any>	<variant> <type_traits> <ratio> <chrono>	<typeindex> <functional> <ctime>
Strings
<string> <string_view> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Ranges
<ranges>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<cfenv> <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
Regular expressions
<regex>
Filesystem support
<filesystem>
Thread support
<thread> <atomic> <mutex>	<shared_mutex> <condition_variable> <future>	<stop_token> <semaphore>	<latch> <barrier>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

This header is part of the strings library.

Classes
chars_format (C++17)	specifies formatting for std::to_chars and std::from_chars (enum)
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 {
    char* ptr;
    errc ec;
    friend bool operator==(const to_chars_result&, const to_chars_result&) = default;
  };
 
  to_chars_result to_chars(char* first, char* last,
                           /* see description */ value, int base = 10);
  to_chars_result to_chars(char* first, char* last, bool value, int base = 10) = delete;
 
  to_chars_result to_chars(char* first, char* last, float value);
  to_chars_result to_chars(char* first, char* last, double value);
  to_chars_result to_chars(char* first, char* last, long double value);
 
  to_chars_result to_chars(char* first, char* last, float value, chars_format fmt);
  to_chars_result to_chars(char* first, char* last, double value, chars_format fmt);
  to_chars_result to_chars(char* first, char* last, long double value, chars_format fmt);
 
  to_chars_result to_chars(char* first, char* last, float value,
                           chars_format fmt, int precision);
  to_chars_result to_chars(char* first, char* last, double value,
                           chars_format fmt, int precision);
  to_chars_result to_chars(char* first, char* last, long double value,
                           chars_format fmt, int precision);
 
 
  // primitive numerical input conversion
  struct from_chars_result {
    const char* ptr;
    errc ec;
    friend bool operator==(const from_chars_result&, const from_chars_result&) = default;
  };
 
  from_chars_result from_chars(const char* first, const char* last,
                               /* see description */& value, int base = 10);
 
  from_chars_result from_chars(const char* first, const char* last, float& value,
                               chars_format fmt = chars_format::general);
  from_chars_result from_chars(const char* first, const char* last, double& value,
                               chars_format fmt = chars_format::general);
  from_chars_result from_chars(const char* first, const char* last, long double& value,
                               chars_format fmt = chars_format::general);
}