pthread_exit and/or pthread_join causing Abort and SegFaults.
- by MJewkes
The following code is a simple thread game, that switches between threads causing the timer to decrease.
It works fine for 3 threads, causes and Abort(core dumped) for 4 threads, and causes a seg fault for 5 or more threads.
Anyone have any idea why this might be happening?
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <errno.h>
#include <assert.h>
int volatile num_of_threads;
int volatile time_per_round;
int volatile time_left;
int volatile turn_id;
int volatile thread_running;
int volatile can_check;
void * player (void * id_in){
int id= (int)id_in;
while(1){
if(can_check){
if (time_left<=0){
break;
}
can_check=0;
if(thread_running){
if(turn_id==id-1){
turn_id=random()%num_of_threads;
time_left--;
}
}
can_check=1;
}
}
pthread_exit(NULL);
}
int main(int argc, char *args[]){
int i;
int buffer;
pthread_t * threads =(pthread_t *)malloc(num_of_threads*sizeof(pthread_t));
thread_running=0;
num_of_threads=atoi(args[1]);
can_check=0;
time_per_round = atoi(args[2]);
time_left=time_per_round;
srandom(time(NULL));
//Create Threads
for (i=0;i<num_of_threads;i++){
do{
buffer=pthread_create(&threads[i],NULL,player,(void *)(i+1));
}while(buffer == EAGAIN);
}
can_check=1;
time_left=time_per_round;
turn_id=random()%num_of_threads;
thread_running=1;
for (i=0;i<num_of_threads;i++){
assert(!pthread_join(threads[i], NULL));
}
return 0;
}
