Isorecursive function type in C

rectype.c

#include <stdio.h>

typedef struct rec rec_t;
typedef rec_t(*ptr_t)();

struct rec
{
    ptr_t ptr;
};

rec_t odd();

rec_t even()
{
    puts("even");
    return (rec_t) { odd };
}

rec_t odd()
{
    puts("odd");
    return (rec_t) { even };
}

int main()
{
    rec_t my_rec = { .ptr = even };

    for (int i = 0; i < 16; ++i)
        my_rec = my_rec.ptr();
}