CS 3733 Operating Systems, Fall 2007 Assignment 4 Comments

• You should not modify the item.h or solution_buffer.c files.
• Do not return negative values from main.
• Do not put the producer or consumer in solution_buffer.c.
• You do not need to allocate space for the solution each time the producer produces something.
  • This is very wasteful.
  • Error handling is difficult.
  • Easy to produce memory leaks.
  • I found memory leaks in half of the programs I graded.
• Dynamic memory allocation should be avoided unless necessary.
  What is wrong with the following code:

      int *i;
      i = (int *)malloc(sizeof(int));
      for (*i=0;*i<10;(*i)++)
         printf("*");
      

• If you use malloc, you need to test for an error and handle the error correctly.
• rand()%N does not produce random values. It may be biased towards smaller numbers for most values of N.
• Do not call exit when a method detects an error.
• Make sure each source file you turn in is labeled.
• There are 2 (or more) ways for the producer to produce an array of unique integers between 0 and N-1:
  
  • For each position in the array, generate a random integer in the right range. Compare to all previously generated values. If not unique, try again.
  • For each number between 0 and N-1, create a random number giving its position in the array. If the array is initially filled with -1's only one test is needed to see if you need to try again.