aligntest.c

#include <stdint.h>
#include <stdio.h>
#include <stddef.h>

typedef void (*test_function_t)();

// Why is `__attribute__((aligned(16)))` necessary? With the default
// alignment of 8, we print a large negative value for limit and then
// don't print any `a` fields.
struct __attribute__((aligned(16))) foo
{
    const char* a;
    uint64_t b;
    test_function_t c;
};

void bar() {}

__attribute__((__section__("mysection")))
static const struct foo data_1 = {
    .a = "hello",
    .b = 1,
    .c = bar
};

__attribute__((__section__("mysection")))
static const struct foo data_2 = {
    .a = "world",
    .b = 2,
    .c = bar
};

int main()
{
    extern struct foo __start_mysection;
    extern struct foo __stop_mysection;
    struct foo* foos = &__start_mysection;
    ptrdiff_t limit = &__stop_mysection - &__start_mysection;
    fprintf(stdout, "limit=%td\n", limit);
    for(int i = 0; i < limit; ++i)
    {
        fprintf(stdout, "%s\n", foos[i].a);
    }
    return 0;
}