sstuff

Examples/concurrency/sem_list2.c

@@ -1,22 +1,24 @@
-/*
- * sem_list2.c - Uses a semaphore as a way to control access
- *               to a critical section for a singly linked list
- */
+s /*
+   * sem_list2.c - Uses a semaphore as a way to control access
+   *               to a critical section for a singly linked list
+   */
 
+#include <pthread.h>
+#include <semaphore.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
 #include <unistd.h>
-#include <pthread.h>
-#include <semaphore.h>
 
-typedef struct node {
-	int val;
-	struct node* next;
+    typedef struct node
+{
+    int val;
+    struct node *next;
 } node;
 
-typedef struct list {
-	node* head;
+typedef struct list
+{
+    node *head;
 } list;
 
 // shared global
@@ -29,71 +31,77 @@ volatile int start = 0;
 sem_t flag;
 
 // The thread process
-void* thread_routine()
+void *thread_routine()
 {
-	printf("Worker thread: %lu ready\n", pthread_self());
-	
-	// wait for start from master thread
-	while(start == 0);
+    printf("Worker thread: %lu ready\n", pthread_self());
 
-	for (int j = 0; j < 1000000; j++)
-	{
-		sem_wait(&flag);
-		node* new_node = malloc(sizeof(node));
-		new_node->val = j;
-		new_node->next = mylist.head;
-		mylist.head = new_node;
-		sem_post(&flag);
-	}
+    // wait for start from master thread
+    while (start == 0)
+        ;
 
-	printf("Worker thread: %lu done\n", pthread_self());
+    for (int j = 0; j < 1000000; j++)
+    {
+        sem_wait(&flag);
+        node *new_node = malloc(sizeof(node));
+        new_node->val = j;
+        new_node->next = mylist.head;
+        mylist.head = new_node;
+        sem_post(&flag);
+    }
 
-	return NULL;
+    printf("Worker thread: %lu done\n", pthread_self());
+
+    return NULL;
 }
 
 // Main process
 int main()
 {
-	sem_init(&flag, 0, 1);
+    sem_init(&flag, 0, 1);
 
-	#define THREAD_COUNT 10
-	pthread_t thr_ids[THREAD_COUNT];
+#define THREAD_COUNT 10
+    pthread_t thr_ids[THREAD_COUNT];
+
+    mylist.head = NULL;
 
-	mylist.head = NULL;
-	
     // Create the threads
-	for(int i = 0; i < THREAD_COUNT; i++) {
-		if(pthread_create(&thr_ids[i], NULL, thread_routine, NULL) == -1) {
-			printf("COULD NOT CREATE A THREAD\n");
-			exit(EXIT_FAILURE);
-		}
-	}
+    for (int i = 0; i < THREAD_COUNT; i++)
+    {
+        if (pthread_create(&thr_ids[i], NULL, thread_routine, NULL) == -1)
+        {
+            printf("COULD NOT CREATE A THREAD\n");
+            exit(EXIT_FAILURE);
+        }
+    }
 
     // Signal threads to start
-	start = 1;
+    start = 1;
 
     // Wait for all threads to finish
-	for(int i = 0; i < THREAD_COUNT; i++) {
-		pthread_join(thr_ids[i],NULL);
-	}
+    for (int i = 0; i < THREAD_COUNT; i++)
+    {
+        pthread_join(thr_ids[i], NULL);
+    }
 
     // Count the elements in the list
-	int length = 0;
-	node* itr = mylist.head;
-	while(itr != NULL) {
-		length++;
-		itr = itr->next;
-	}
-	printf("List contains %d elements\n", length);
+    int length = 0;
+    node *itr = mylist.head;
+    while (itr != NULL)
+    {
+        length++;
+        itr = itr->next;
+    }
+    printf("List contains %d elements\n", length);
 
     // Free the list
-	while(mylist.head != NULL) {
-		node* to_delete = mylist.head;
+    while (mylist.head != NULL)
+    {
+        node *to_delete = mylist.head;
         mylist.head = mylist.head->next;
         free(to_delete);
-	}
-	
+    }
+
     sem_destroy(&flag);
 
-	return EXIT_SUCCESS;
+    return EXIT_SUCCESS;
 }