/*
 * sample-c23.c: features new in C23 (ISO/IEC 9899:2024).
 * Free sample from 99helpers.com/file-types/c
 *
 * Needs a compiler in C23 mode. It fails under -std=c17, which makes it a
 * handy test of which standard a build uses.
 *     gcc -Wall -Wextra -std=c23 sample-c23.c -o sample-c23   (GCC 14 and later;
 *                                     GCC 13 calls it -std=c2x; GCC 15 and
 *                                     later use C23 by default)
 *     clang -Wall -Wextra -std=c23 sample-c23.c -o sample-c23 (Clang 18 and later)
 */
#include <stdio.h>

/* [[attributes]] use the same syntax as C++. nodiscard warns if a caller
 * ignores the result. */
[[nodiscard]] static int clamp_percent(int value)
{
    return value < 0 ? 0 : value > 100 ? 100 : value;
}

int main(void)
{
    /* bool, true and false are keywords now: no <stdbool.h> needed. */
    bool ready = true;

    /* nullptr is a real null pointer constant with its own type. */
    const char *label = nullptr;

    /* Binary literals and digit separators make constants readable. */
    unsigned flags = 0b1010'0101;
    long long population = 8'100'000'000;

    /* typeof, long a GCC extension, is now standard: it names the type of
     * an expression, here long long. */
    typeof(population) copy = population / 1'000;

    /* static_assert no longer needs a message, and needs no header. */
    static_assert(sizeof(long) >= 4);

    if (label == nullptr) {
        label = "C23";
    }
    printf("%s: ready=%d flags=0x%X copy=%lld percent=%d\n", label, ready,
           flags, copy, clamp_percent(140));
    printf("__STDC_VERSION__ = %ldL\n", (long)__STDC_VERSION__);
    return 0;
}