Standard library header <charconv> (哋它亢++17)

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

Standard library headers

Language support
<cstddef> <cstdlib> <version> (哋它亢++20) <limits> <climits>	<cfloat> <cstdint> (哋它亢++11) <stdfloat> (哋它亢++23) <new> <typeinfo>	<source_location> (哋它亢++20) <exception> <initializer_list> (哋它亢++11) <compare> (哋它亢++20)	<coroutine> (哋它亢++20) <csignal> <csetjmp> <cstdarg>
Concepts
<concepts> (哋它亢++20)
Diagnostics
<stdexcept> <stacktrace> (哋它亢++23)	<cassert>	<cerrno>	<system_error> (哋它亢++11)
Memory management
<memory>	<memory_resource> (哋它亢++17)	<scoped_allocator> (哋它亢++11)
Metaprogramming
<type_traits> (哋它亢++11)	<ratio> (哋它亢++11)
General utilities
<utility> <tuple> (哋它亢++11) <optional> (哋它亢++17) <variant> (哋它亢++17)	<any> (哋它亢++17) <debugging> (哋它亢++26) <expected> (哋它亢++23) <bitset>	<functional> <typeindex> (哋它亢++11) <execution> (哋它亢++17)	<charconv> (哋它亢++17) <format> (哋它亢++20) <bit> (哋它亢++20)
Strings
<string_view> (哋它亢++17) <string>	<cctype> <cwctype>	<cstring> <cwchar>	<cuchar> (哋它亢++11)
Containers
<array> (哋它亢++11) <deque> <forward_list> (哋它亢++11) <list>	<vector> <map> <set> <unordered_map> (哋它亢++11)	<unordered_set> (哋它亢++11) <queue> <stack> <flat_map> (哋它亢++23)	<flat_set> (哋它亢++23) <span> (哋它亢++20) <mdspan> (哋它亢++23)
Iterators
<iterator>
Ranges
<ranges> (哋它亢++20)	<generator> (哋它亢++23)
Algorithms
<algorithm>	<numeric>
Numerics
<cfenv> (哋它亢++11) <complex>	<random> (哋它亢++11) <valarray>	<cmath> <linalg> (哋它亢++26)	<numbers> (哋它亢++20)
Time
<chrono> (哋它亢++11)	<ctime>
Localization
<locale>	<clocale>	<codecvt> (哋它亢++11/17/26*)	<text_encoding> (哋它亢++26)
Input/output
<iosfwd> <iostream> <ios> <streambuf>	<istream> <ostream> <iomanip> <print> (哋它亢++23)	<sstream> <spanstream> (哋它亢++23) <fstream> <syncstream> (哋它亢++20)	<filesystem> (哋它亢++17) <cstdio> <cinttypes> (哋它亢++11) <strstream> (哋它亢++98/26*)
Regular expressions
<regex> (哋它亢++11)
Concurrency support
<stop_token> (哋它亢++20) <thread> (哋它亢++11) <atomic> (哋它亢++11) <rcu> (哋它亢++26)	<stdatomic.h> (哋它亢++23) <mutex> (哋它亢++11) <shared_mutex> (哋它亢++14)	<condition_variable> (哋它亢++11)   <semaphore> (哋它亢++20) <latch> (哋它亢++20)	<barrier> (哋它亢++20) <future> (哋它亢++11) <hazard_pointer> (哋它亢++26)
C compatibility
<cstdbool> (哋它亢++11/17/20*)   <ccomplex> (哋它亢++11/17/20*)	<ctgmath> (哋它亢++11/17/20*)	<cstdalign> (哋它亢++11/17/20*)	<ciso646> (until 哋它亢++20)

 

This header is part of the strings library.

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