Member Avatar for Mr.UNOwen

Hello,

So I'm having trouble figuring out what the correct syntax is for a function with a return type that is a template type and is within a namespace. Anyone see anything wrong with the code below?

-------.HPP file:

#pragma once

#ifndef EC_UTIL_H
#define EC_UTIL_H

#include "../CommonHeaders.hpp"
#include "../core/common/APVertex.hpp"

#include <QString>

class QWidget;

namespace EditorCommon
{ 
   template <class T> T *findAndAssert(QString id, QWidget *root);
}

#endif



#include "ECUtil.hpp"

------------------- .CPP file:

#include <QApplication>
#include <QWidget>
#include <QMessageBox>

namespace EditorCommon
{
   template <class T> T *findAndAssert(QString id, QWidget *root)
   {
      T *w = root->findChild<T *>(id);

      if(!w)
      {
         QMessageBox::critical(root , QString("Critical Application Error"), QString("Missing UI element: ") + id);
         exit(EXIT_FAILURE);
      }

      return w;
   }
}

------- In use:

mColumn.mEnableSnap = (QCheckBox *) findAndAssert<QWidget>(QString("uiEnableSnap"), panel);

------ Error:
WorkspaceDelegate.cpp:(.text+0x141): undefined reference to `QWidget* EditorCommon::findAndAssert<QWidget>(QString, QWidget*)'

  • 2 Contributors
  • 1 Reply
  • 345 Views
  • 50 Minutes Discussion Span
  • Latest Post Latest Post by sepp2k
Member Avatar for sepp2k

The syntax is right, but for template functions the definition needs to be in the header file, not the .cpp file.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.