C++ Handbook

Header Reference: <charconv>

Header Reference: <charconv>

Locale-independent low-level numeric parsing and formatting utilities from <charconv>.

How to use this reference page

Use reference pages to confirm names, categories, nearby facilities, and the constraints that matter before writing or reviewing code.

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  • Use the nearby-page links when your question is really about a companion header, related algorithm family, or broader subsystem.
  • Validate tricky behavior with a small compileable example before relying on memory for details like invalidation, ordering, allocation, or lifetime rules.

What header pages are for

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  • Use the example section below as a minimal pattern, then adapt it to your real container, ownership, text, or concurrency workflow.
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Header Reference: <charconv>

Main facilities

What this header is for

Use <charconv> for fast, allocation-free number parsing and formatting into caller-provided buffers.

Typical use cases

Notes

Minimal example

#include <charconv>
#include <array>

int main() {
    std::array<char, 16> buffer{};
    auto [ptr, ec] = std::to_chars(buffer.data(), buffer.data() + buffer.size(), 42);
    return ec == std::errc{} ? 0 : 1;
}

What to verify before relying on this header

  • Whether the code needs ownership, borrowing, locale awareness, or low-allocation conversion behavior.
  • How errors are reported: stream state, parse result, exception, error code, or boolean match result.
  • Whether encoding, formatting, or lifetime assumptions need to be made explicit in the surrounding API.