#include <stdio.h>
#include <unistd.h>
int main(void)
{
setvbuf(stderr, NULL, _IOFBF, BUFSIZ);
setvbuf(stdout, NULL, _IONBF, 0);
fprintf(stderr, "stderr");
fprintf(stdout, "stdout");
sleep(1);
printf("\n");
return 0;
}