Previously we had said that off_t was a reasonable type to hold the result of offsetof(). That isn't so: ptrdiff_t is correct.
@@ -195,7 +195,7 @@
* structure <b>st</b>. Example:
* <pre>
* struct a { int foo; int bar; } x;
- * off_t bar_offset = offsetof(struct a, bar);
+ * ptrdiff_t bar_offset = offsetof(struct a, bar);
* int *bar_p = STRUCT_VAR_P(&x, bar_offset);
* *bar_p = 3;
* </pre>