- uschar buffer[ADDRESS_MAXLENGTH + 20];
- int n = sprintf(CS buffer, "Return-path: <%.*s>\n", ADDRESS_MAXLENGTH,
- return_path);
- if (!write_chunk(tctx, buffer, n)) goto bad;
+ int n;
+ uschar * s = string_sprintf("Return-path: <%.*s>\n%n",
+ EXIM_EMAILADDR_MAX, return_path, &n);
+ if (!write_chunk(tctx, s, n)) goto bad;