using something like rust Result in C?

result-type-in.c

#include <stdbool.h>
#include <stdio.h>

#define DEFINE_RESULT(T, E, NAME) \
typedef struct { \
  bool success : 1; \
  union { \
    T result; \
    E error; \
  }; \
} NAME;

DEFINE_RESULT(int, int, Result)

Result func_1(int x) {
  Result r = { success: true, result: 0 };

  if (x >= 0) {
    r.result = x * 2;
  } else {
    r.success = false;
    r.error = 1;
  }

  return r;
}

int func_2(int x, int* res) {
  if (x >= 0) {
    *res = x * 2;
    return 0;
  } else {
    return 1;
  }
}

int main() {
  Result r;
  int x;
  int e;

  for (int i = -1; i < 2; ++i) {
    r = func_1(i);
    if (r.success) {
      printf("result is %d\n", r.result);
    } else {
      switch (r.error) {
        // ...
        default:
          printf("error set to %d\n", r.error);
      }
    }
  }

  for (int i = -1; i < 2; ++i) {
    e = func_2(i, &x);
    if (e == 0) {
      printf("result is %d\n", x);
    } else {
      switch (e) {
        // ...
        default:
          printf("error set to %d\n", e);
      }
    }
  }

  return 0;
}

Coming from swift and hacking in a bit of C lately, I was looking for something like this, thanks!