int main(void)
{
int num,i;
printf("input a positive number:" );
scanf("%d",&num);
printf("all the primes <= %d:\n",num);
for(i=2; i<=num; i++)
if(isprimer(i))
printf("%d\t",i );
printf("\n");
return 0;
}
int main(){
int* p = mmap(0,4,PROT_READ|PROT_WRITE,MAP_SHARED,0,0);
int id = 1;
int a,b;
while(1){
if(id == 1){
a = 1;
b = 5000;
}
if(id == 2){
a = 5000;
b = 10000;
}
if(fork()){
if(++id>2){
int fd = open("primer.dat",
O_RDWR|O_CREAT,0666);
if(fd == -1){
printf("open error:%m\n");
exit(-1);
}
int* q = p;
while(q != NULL){
printf("%d\n",*q++);
//write(fd,*q++,sizeof(int));
}
close(fd);
}
}else{
int i;
int r;
int* q = p;
for(i = a ; i < b ; i ++){
r = isprimer(i);
if(r == 1){
*q++ = i;
}
}
printf("pid:%d task complete!\n",getpid());
exit(0);
}
}
return 0;
}
