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| #include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#define THREAD_NUM 20
pthread_mutex_t AccountA_mutex;
pthread_mutex_t AccountB_mutex;
struct Account {
char account_name[1];
int balance;
};
struct Account accountA = {'A', 100000};
struct Account accountB = {'B', 200000};
void * accountAB (void* amount_ptr) {
int amount = *((int*)amount_ptr);
pthread_mutex_lock(&AccountA_mutex);
if (accountA.balance < amount) {
printf("There is not enough memory in Account A!\n");
pthread_mutex_unlock(&AccountA_mutex);
pthread_exit((void *)1);
}
accountA.balance -=amount;
sleep(2);
pthread_mutex_lock(&AccountB_mutex);
accountB.balance +=amount;
pthread_mutex_unlock(&AccountA_mutex);
pthread_mutex_unlock(&AccountB_mutex);
}
void * accountBA (void* amount_ptr) {
int amount = *((int*)amount_ptr);
pthread_mutex_lock(&AccountB_mutex);
if (accountB.balance < amount) {
printf("There is not enough memory in Account B!\n");
pthread_mutex_unlock(&AccountB_mutex);
pthread_exit((void *)1);
}
accountB.balance -=amount;
pthread_mutex_lock(&AccountA_mutex);
accountA.balance +=amount;
pthread_mutex_unlock(&AccountB_mutex);
pthread_mutex_unlock(&AccountA_mutex);
}
int main(int argc, char* argv[]) {
int threadid[THREAD_NUM];
pthread_t pthread[THREAD_NUM];
void* thResState;
int res, flag;
int transfer_amount[THREAD_NUM] = {100, 200, 300, 400,100,200,300,400,500,600,700,800,900,800,700,600,500,400,300,200};
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
for(flag=0; flag<THREAD_NUM; flag++){
if(flag%2 == 0){
if (threadid[flag] = pthread_create(&pthread[flag], &attr , accountAB, \
(void*)&transfer_amount[flag]) < 0){
printf("Thread %d creation failed\n", flag);
exit (1);
}
}
else{
if (threadid[flag] = pthread_create(&pthread[flag], &attr , accountBA, \
(void*)&transfer_amount[flag]) < 0) {
printf("Thread %d creation failed\n", flag);
exit (1);
}
}
}
for(flag=0; flag<THREAD_NUM; flag++){
res = pthread_join(pthread[flag], &thResState);
if (res != 0){
perror("Thread join failed");
exit(-1);
}
printf("thread success id %u state code %d\n",threadid[flag],thResState);
}
printf("Transitions are in progress..");
printf("\nAll the money is transferred !!\n");
}
|