不可重入函数测试

#include <signal.h>
#include <stdio.h>
struct two_int { int a, b; } data;
void signal_handler(int signum){
printf ("%d, %d\n", data.a, data.b);
alarm (1);
}
int main (void){
static struct two_int zeros = { 0, 0 }, ones = { 1, 1 }, twos = {2,2};
signal (SIGALRM, signal_handler);
data = zeros;
alarm (1);
while (1)
{data = zeros; data = ones; data = twos;}
}