c语言版本的coroutine

#include <stdio.h>

int function(void) {
    static int i, state = ;
    switch (state) {
        case : goto LABEL0;
        case : goto LABEL1;
    }
    LABEL0: /* start of function */
    for (i = ; i < ; i++) {
        state = ; /* so we will come back to LABEL1 */
        return i;
        LABEL1:; /* resume control straight after the return */
    }
}

int main(){
  printf(":%d\n" , function());
  printf(":%d\n" , function());
  printf(":%d\n" , function());
  printf(":%d\n" , function());
  printf(":%d\n" , function());
  return ;
}

想过，但是没想到，还真有啊！