Code density and documentation

• (Reminder, see File layout) Lines MUST NOT exceed 80 characters in width, including the trailing newline character.
• Function definitions SHOULD be preceded by a comment explaining the purpose of the function. This explanatory comment SHOULD contain a description of the arguments, the error cases, the return value (if any) and the algorithm realized by the function.

  This is recommended:

            
  
            /*
            ** my_strlen: "strlen" equivalent
            **   str: the string
            **   return value: the number of characters
            ** my_strlen counts the number of characters in [str], not
            ** counting the final '\0' character.
            */
            size_t    my_strlen(const char *str);
            {
               /* definition of my_strlen */
            }
            
            

• Function bodies MUST NOT contain comments. Any useful notice should appear before the function.
• There MUST NOT be any blank line elsewhere than between declarations and statements within a function body.
• Function bodies MUST NOT contain more than 25 lines, enclosing braces excluded.

  Rationale: function bodies should be kept short.

• Many functions from the C library, as well as some system calls, return status values. Although special cases MUST be handled, the handling code MUST NOT clobber an algorithm. Therefore, special versions of the library or system calls, containing the error handlers, SHOULD be introduced where appropriate.

  For example:

            
  
            void    *xmalloc(size_t n)
            {
              void  *p;
            
              p = malloc(n);
              if (p == 0)
              {
                fprintf(stderr, "Virtual memory exhausted.\n");
                exit(1);
              }
              return p;
            }