RISC Machine Data Structure Word Alignment Problems?

[Peter da Silva]

> (%): Even the guarantee, that the struct elements are at ascending
> adresses in the order they are declared, IMHO only was given
> to avoid complex (and hard to understand) rules, when and when
> not it would be allowed to rearrange the elements. Readers who
> know other good reasons why this guarantee is given are welcome
> to correct me (hello Chris :-)).

It makes the following two practices reasonably portable:

1:
	struct list_header {
		struct list_header next, prev;
	};

	struct object {
		struct list_header list;
		...
	};

	struct list_header *my_list == NULL;
	struct object my_object;
	extern add_list(struct list_header **list, struct list_header *elt);

	add_list(&my_list, &my_object);

2:
	struct buffer {
		int len;
		char *next;
		char data[1];
	};

	struct buffer *new_buffer(size)
	int size;
	{
		struct buffer *temp;
		
		temp = (struct buffer *) malloc(sizeof *temp + size);
		if(temp) {
			temp->len = size;
			temp->next = &temp->data[0];
		}
		return temp;
	}
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 _--_|\  Peter da Silva. +1 713 274 5180. <peter at ficc.uu.net>.
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