多线程编程

typedef  struct ct_sum

{    

int  sum;

pthread_mutex_t lock;

}ct_sum;

void  * add1( void * cnt)

{

pthread_mutex_lock(&(((ct_sum*)cnt)->lock));

int  i;

for ( i=0;i<50;i++){

(*(ct_sum*)cnt).sum+=i;}

pthread_mutex_unlock(&(((ct_sum*)cnt)->lock));

pthread_exit(NULL);

return  0;

}

void  * add2( void *cnt)

{

int  i;

cnt= (ct_sum*)cnt;

pthread_mutex_lock(&(((ct_sum*)cnt)->lock));

for ( i=50;i<101;i++)

{    (*(ct_sum*)cnt).sum+=i;

}

pthread_mutex_unlock(&(((ct_sum*)cnt)->lock));

pthread_exit(NULL);

return  0;

}

int  main( void)

{    int  i;

pthread_t ptid1,ptid2;

int  sum=0;

ct_sum cnt;

pthread_mutex_init(&(cnt.lock),NULL);

cnt.sum=0;

pthread_create(&ptid1,NULL,add1,&cnt);

pthread_create(&ptid2,NULL,add2,&cnt);

pthread_mutex_lock(&(cnt.lock));

printf( "sum %d\n" ,cnt.sum);

pthread_mutex_unlock(&(cnt.lock));

pthread_join(ptid1,NULL);

pthread_join(ptid2,NULL);

pthread_mutex_destroy(&(cnt.lock));

return  0;

}