int rc = 0;
  char * z = (char*)P("QUERY_STRING");
  if( z ){
    ++rc;
    z = fossil_strdup(z);
    add_param_list(z, '&');
    z = (char*)P("skin");
    if( z ){
      char *zErr = skin_use_alternative(z, 2);
      ++rc;
      if( !zErr && P("once")==0 ){
        cookie_write_parameter("skin","skin",z);
        /* Per /chat discussion, passing ?skin=... without "once"
        ** implies the "udc" argument, so we force that into the
        ** environment here. */
        cgi_set_parameter_nocopy("udc", "1", 1);
      }
      fossil_free(zErr);
    }
  }
  return rc;
}

  const char *zDflt      /* Default value for the parameter */
){
  cookie_readwrite(zQP, zPName, zDflt, COOKIE_READ|COOKIE_WRITE);
}

/* Update the user preferences cookie, if necessary, and shut down
** this module. The cookie is only emitted if its value has actually
** changed since the request started and the "udc" (Update Display
** Cookie) URL argument was provided.
**
** Historical note: from 2021-03-02 [71a2d68a7a113e7c] until
** 2023-01-16, the udc was not observed (it had been prior to that),
** and that led to the unfortunate side effect that a timeline link
** from the /reports page would end up persistently setting a user's
** timeline length preference to the number of items in that
** report. In a /chat discussion it was agreed that updating the
** cookie requires explicit opt-in via the udc argument or ?skin=...,
** which implies udc.
*/
void cookie_render(void){
  if( cookies.bChanged && P("udc")!=0 ){
    Blob new;
    int i;
    blob_init(&new, 0, 0);
    for(i=0;i<cookies.nParam;i++){
      if( i>0 ) blob_append(&new, ",", 1);
      blob_appendf(&new, "%s=%T",
          cookies.aParam[i].zPName, cookies.aParam[i].zPValue);

       "<div class=\"section accordion\">References</div>\n");
  @ <div class="section accordion">Context</div><div class="accordion_panel">
  render_checkin_context(rid, 0, 0, 0);
  @ </div><div class="section accordion">Changes</div>
  @ <div class="accordion_panel">
  @ <div class="sectionmenu">
  pCfg = construct_diff_flags(diffType, &DCfg);
  DCfg.pRe = pRe;
  zW = (DCfg.diffFlags&DIFF_IGNORE_ALLWS)?"&w":"";
  if( diffType!=0 ){
    @ %z(chref("button","%R/%s/%T?diff=0",zPageHide,zName))\
    @ Hide&nbsp;Diffs</a>
  }
  if( diffType!=1 ){
    @ %z(chref("button","%R/%s/%T?diff=1%s",zPage,zName,zW))\

  );
  while( db_step(&q3)==SQLITE_ROW ){
    const char *zName = db_column_text(&q3,0);
    int mperm = db_column_int(&q3, 1);
    const char *zOld = db_column_text(&q3,2);
    const char *zNew = db_column_text(&q3,3);
    const char *zOldName = db_column_text(&q3, 4);
    append_file_change_line(zUuid, zName, zOld, zNew, zOldName,
                            pCfg,mperm);
  }
  db_finalize(&q3);
  @ </div>
  append_diff_javascript(diffType);
  style_finish_page();
}

}

/*
** Send an HTTP redirect back to the designated Index Page.
*/
NORETURN void fossil_redirect_home(void){
  /* In order for ?skin=... to work when visiting the site from
  ** a typical external link, we have to process it here, as
  ** that parameter gets lost during the redirect. We "could"
  ** pass the whole query string along instead, but that seems
  ** unnecessary. */
  if(cgi_setup_query_string()>1){
    cookie_render();
  }
  cgi_redirectf("%R%s", db_get("index-page", "/index"));

  /* Add document end mark if it was not in the footer */
  if( sqlite3_strlike("%</body>%", zFooter, 0)!=0 ){
    style_load_all_js_files();
    @ </body>
    @ </html>
  }
  /* Update the user display prefs cookie if it was modified */


  cookie_render();
}

/*
** Begin a side-box on the right-hand side of a page.  The title and
** the width of the box are given as arguments.  The width is usually
** a percentage of total screen width.