Wt

I sometimes got segmentation faults with the very same stacktrace [see below]. Apparantly it was because of a resize of a certain widget with a ridiculous width (either extremely high, or extremely small).

I traced it down to the treeroot in the code below. Re-arranging the code so the addColumn's happen BEFORE the setTreeNode fixed the issue [which I got in around 10% of the times I tried to reproduce the issue].

I would suggest two things:

1. Add a runtime warning when adding columns after the treenode has been set [I know it is allready in the docs, but people as myself clearly missed it slap on my hands]
   
2. Add a runtime check in WLength so you cannot go past the bounds of unitText, and give a warning there as well when this would happen

The problem for a user of your library is finding out what the issue in his code is, because the stacktrace is completely within Wt code.

Code:

WTreeTableNode *root = new file_treetable_node_widget(mount_point_);

setTreeRoot(root, "file");

treeRoot()->setNodeVisible(false);

addColumn("size", 60);

addColumn("modified", 140);

stacktrace:

Wt::WLength::cssText() at WLength.C:119 0xb7c792b3 line std::strcat(buf, unitText[unit*]); next to width, the unit* was also far to big, so it would go past the array and give the segmentation fault

Wt::WWebWidget::updateDom() at WWebWidget.C:1,267 0xb7d68fa5 line element.setProperty(PropertyStyleWidth, width_->cssText());

Wt::WInteractWidget::updateDom() at WInteractWidget.C:325 0xb7c6ea25

Wt::WText::updateDom() at WText.C:115 0xb7d27899

Wt::WWebWidget::createDomElement() at WWebWidget.C:1,780 0xb7d65e2c

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WTable::createRow() at WTable.C:327 0xb7d0bfdf

Wt::WTable::createDomElement() at WTable.C:291 0xb7d0c4ac

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WTable::createRow() at WTable.C:327 0xb7d0bfdf

Wt::WTable::createDomElement() at WTable.C:291 0xb7d0c4ac

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::StdWidgetItemImpl::createDomElement() at StdWidgetItemImpl.C:56 0xb7b795da

Wt::StdGridLayoutImpl::createDomElement() at StdGridLayoutImpl.C:482 0xb7b75494

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:666 0xb7c056d8

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WStackedWidget::createDomElement() at WStackedWidget.C:137 0xb7ce2f94

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::createDomChildren() at WContainerWidget.C:721 0xb7c0578d

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:654 0xb7c05eab

Wt::WContainerWidget::createDomElement() at WContainerWidget.C:642 0xb7c05eec

Wt::WWebWidget::createActualElement() at WWebWidget.C:1,823 0xb7d6380f

Wt::WWidget::createSDomElement() at WWidget.C:316 0xb7d7948c

Wt::WContainerWidget::updateDomChildren() at WContainerWidget.C:749 0xb7c04872

Wt::WContainerWidget::getDomChanges() at WContainerWidget.C:633 0xb7c05f5f

Wt::WWebWidget::getSDomChanges() at WWebWidget.C:1,683 0xb7d66036

Wt::WebRenderer::collectChanges() at WebRenderer.C:1,286 0xb7deca9c

Wt::WebRenderer::collectJS() at WebRenderer.C:1,367 0xb7dee80e

Wt::WebRenderer::collectJavaScriptUpdate() at WebRenderer.C:1,299 0xb7def1b6

Wt::WebRenderer::collectJavaScript() at WebRenderer.C:536 0xb7df5d17

Wt::WebRenderer::serveJavaScriptUpdate() at WebRenderer.C:459 0xb7df79dd

Wt::WebRenderer::serveResponse() at WebRenderer.C:194 0xb7df8d64

Wt::WebSession::serveResponse() at WebSession.C:1,990 0xb7dda690

Wt::WebSession::render() at WebSession.C:1,945 0xb7de0812

Wt::WebSession::notify() at WebSession.C:1,841 0xb7de3d5a

Wt::WApplication::notify() at WApplication.C:1,358 0xb7bae9a7

Wt::WebSession::handleRequest() at WebSession.C:1,288 0xb7ddda1a

Wt::WebController::handleAsyncRequest() at WebController.C:644 0xb7dfe67f

Wt::WebController::handleRequest() at WebController.C:515 0xb7dff6e4

Wt::WServer::handleRequest() at WServer.C:372 0xb7a23a9a

http::server::WtReply::consumeRequestBody() at WtReply.C:182 0xb7a29d6c

http::server::WtReply::consumeData() at WtReply.C:81 0xb7a2b82c

http::server::RequestParser::parseBody() at RequestParser.C:135 0xb7a0392c

http::server::Connection::handleReadBody() at Connection.C:191 0xb79eb752

http::server::Connection::handleReadRequest0() at Connection.C:127 0xb79eda28

http::server::Connection::handleReadRequest() at Connection.C:162 0xb79edc5a

boost::asio::detail::reactive_socket_recv_op<boost::asio::mutable_buffers_1, boost::_bi::bind_t<void, boost::_mfi::mf2<void, http::server::Connection, boost::system::error_code const&, unsigned int>, boost::_bi::list3<boost::_bi::value<boost::shared_ptrhttp::server::Connection >, boost::arg<1> () at 0xb7a224f3

boost::asio::detail::task_io_service::run() at 0xb7a0e8b5

boost::asio::io_service::run() at io_service.ipp:57 0xb7a053ee

http::server::Server::run() at Server.C:204 0xb7a053ee

Wt::WServerImpl::runThread() at 0xb7a262eb

boost::detail::thread_data<boost::_bi::bind_t<void, boost::_mfi::mf1<void, Wt::WServerImpl, Wt::WServer*, boost::_bi::list2<boost::_bi::value<Wt::WServerImpl*>, boost::_bi::value<Wt::WServer*> > > >::run() at 0xb7a260f2

thread_proxy() at 0xb77b1dfc

start_thread() at pthread_create.c:300 0xb620c955

clone() at clone.S:130 0xb62ebe7e