#include <pthread.h>
#include <stdio.h>
#define NTHREADS 4
#define N 1000
#define MEGEXTRA 1000000
pthread_attr_t attr;
void *dowork(void *threadid)
{
double A[N][N];
int i,j,tid;
size_t mystacksize;
tid = (int)threadid;
pthread_attr_getstacksize (&attr, &mystacksize);
printf("Thread %d: stack size = %li bytes \n", tid, mystacksize);
for (i=0; i<N; i++)
for (j=0; j<N; j++)
A[i][j] = ((i*j)/3.452) + (N-i);
pthread_exit(NULL);
}
int main(int argc, char *argv[])
{
pthread_t threads[NTHREADS];
size_t stacksize;
int rc, t;
pthread_attr_init(&attr);
pthread_attr_getstacksize (&attr, &stacksize);
printf("Default stack size = %li\n", stacksize);
stacksize = sizeof(double)*N*N+MEGEXTRA;
printf("Amount of stack needed per thread = %li\n",stacksize);
pthread_attr_setstacksize (&attr, stacksize);
printf("Creating threads with stack size = %li bytes\n",stacksize);
for(t=0; t<NTHREADS; t++){
rc = pthread_create(&threads[t], &attr, dowork, (void *)t);
if (rc){
printf("ERROR; return code from pthread_create() is %d\n", rc);
exit(-1);
}
}
printf("Created %d threads.\n", t);
pthread_exit(NULL);
}
