Aufgabe04-1

aufgabe03/aufgabe1.d

-aufgabe1.o: aufgabe1.c

aufgabe04/Makefile

+# This makefile compiles all C files in the same directory and produces a single
+# executable named solution
+CC = gcc
+CFLAGS = -std=c11 -Wall -Wextra -pedantic -O2 -g -pthread  # this uses the C11 standard, if you want to use a different standard, change it to -std=c[NUMBER]
+CPPFLAGS = -MMD
+LD_FLAGS = -lm
+
+BIN_NAME = solution
+SRC_FILES = $(wildcard *.c)
+OBJ_FILES = $(SRC_FILES:.c=.o) 
+DEP_FILES = $(wildcard *.d)
+
+run: $(BIN_NAME)
+	./$(BIN_NAME)
+
+include $(DEP_FILES)
+
+$(BIN_NAME): $(OBJ_FILES)
+	$(CC) $(CPPFLAGS) $(LD_FLAGS) $(OBJ_FILES) -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@ 
+
+clean:	
+	@rm -v *.o *.d
+	@rm -v ./$(BIN_NAME)
+
+.PHONY: run clean

aufgabe04/aufgabe1.c

+// dining philosophers with unshared chopsticks
+#include <stdio.h> 
+#include <stdlib.h>
+#include <pthread.h> 
+#include <unistd.h> 
+
+#define NUM_THREADS     5
+pthread_mutex_t lock;
+int chopsticks[NUM_THREADS];
+
+void* Philosopher (void *threadid) 
+{
+  long tid;
+  tid = (long)threadid;
+  int _error = 0;
+
+  for (int i= 0; i < 10; i++) {
+    // thinking
+    sleep (0.5);
+
+    //wait 
+    
+    //Beginn kritischer Abschnitt
+    _error = pthread_mutex_lock(&lock);
+    
+    //Warten darauf, dass chopstick frei werden
+    while (chopsticks[tid] + chopsticks[(tid + 1) % NUM_THREADS] < 2);
+    
+    chopsticks[tid] = 0;
+    chopsticks[(tid + 1) % NUM_THREADS] = 0;
+    
+    _error = pthread_mutex_unlock(&lock);
+    //Ende kritischer Abschnitt
+
+    printf("\n %ld Dining..\n", tid); 
+    sleep(0.5); 
+    printf("\n %ld Finished..\n", tid); 
+    
+    //Beginn kritischer Abschnitt
+    _error = pthread_mutex_lock(&lock);
+    chopsticks[tid] = 1;
+    chopsticks[(tid + 1) % NUM_THREADS] = 1;
+    _error = pthread_mutex_unlock(&lock);
+    //Ende kritischer Abschnitt
+  }
+} 
+
+
+int main (void) 
+{ 
+  pthread_t threads[NUM_THREADS];
+  int rc;
+  long t;
+
+  for(int i=0;i<NUM_THREADS;i++){
+    chopsticks[i]=1;
+  }
+
+  for(t=0; t < NUM_THREADS; t++) {
+     printf ("In main: creating thread %ld\n", t);
+     rc = pthread_create (&threads[t], NULL, Philosopher, (void *)t);
+     if (rc) {
+        printf ("ERROR; return code from pthread_create () is %d\n", rc);
+        exit (-1);
+     }
+  }
+
+  for(t=0; t < NUM_THREADS; t++) {
+     pthread_join (threads[t], NULL);
+  }
+
+  return 0; 
+} 
+