Commit ec89e787 ec89e787174ad0acb3a8b59f92613fd4738c1860 by

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#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
int calcpi() {
int r[2800 + 1];
int i, k;
int b, d;
int c = 0;
for (i = 0; i < 2800; i++) {
r[i] = 2000;
}
for (k = 2800; k > 0; k -= 14) {
d = 0;
i = k;
for (;;) {
d += r[i] * 10000;
b = 2 * i - 1;
r[i] = d % b;
d /= b;
i--;
if (i == 0) break;
d *= i;
}
c = d % 10000;
}
return 0;
}
void * thread_main(void * ptr) {
while (1 == 1) calcpi();
}
int main(int argc, char * * argv) {
if(argc < 2) {
printf("\nUsage: %s <n> <p>\n\nWhere\n<n> is the number of threads to run in parallell\n<p> is the priority (optional)\n\n", argv[0]);
return 0;
}
int numT = atoi(argv[1]);
printf("\nStarting %d threads calculating PI. Hit Cntrl-C to stop or send a kill signal\n",numT);
pthread_t lastT;
int prio = 0;
if(argc == 3) {
prio = atoi(argv[2]);
errno = 0;
int res = nice(prio);
if(errno != 0) {
printf("Setting nice %d failed (code %d), are you root?\n", prio, errno);
} else {
printf("Process nice value set to %d\n", res);
}
}
for(int x=0; x < numT; x++) {
pthread_create(&lastT, NULL, thread_main, NULL);
}
pthread_join(lastT, NULL);
exit(0);
}