#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void only(size_t size, char buffer[restrict static size + 1]) [[reproducible]] {
    for (size_t i = 0; i < size; ++i) {
        buffer[i] = 'X';
    }
}

int main(void) {
    char value[] = "test 1 2 3";
    only(strlen(value), value);
    printf("%s\n", value);
    return EXIT_SUCCESS;
}