linker errors for QWidget

MohsinM.

I am getting ~40 or so linker errors for QWidget - examples below.

VS 2017 project is referencing Qt5Guid.lib with directory: C:\Qt\Qt-5.12.1\lib
qt5Guid.lib file is present 9,452 kb
Other QT5 libs are being detected fine (ex: Qt5Cored.lib, Qt5OpenGLd.lib)

Error LNK2001 unresolved external symbol "protected: virtual void __thiscall QWidget::actionEvent(class QActionEvent *)" (?actionEvent@QWidget@@MAEXPAVQActionEvent@@@Z) SandBoxGame C:\Projects\SandBoxGame\main.obj 1
Error LNK2001 unresolved external symbol "protected: virtual void __thiscall QWidget::changeEvent(class QEvent *)" (?changeEvent@QWidget@@MAEXPAVQEvent@@@Z) SandBoxGame C:\Projects\SandBoxGame\main.obj 1
Error LNK2001 unresolved external symbol "protected: virtual void __thiscall QWidget::closeEvent(class QCloseEvent *)" (?closeEvent@QWidget@@MAEXPAVQCloseEvent@@@Z) SandBoxGame C:\Projects\SandBoxGame\main.obj 1

SGaist

Hi,

Did you add QT += widgets to your .pro file ?
If so, did you then run qmake before building ?

MohsinM.

Didn't use pro file. Background and code if it helps:
needed opengl desktop so did the following:
download source code for 5.12.1
open VS 2017 developer cmd
cd C:\Qt\5.12.1\Src
configure -debug-and-release -opengl desktop
nmake
nmake install

main.cpp
#include <QtWidgets\qapplication.h>
#include "myGlWindow.h"

int main(int argc, char* argv[])
{
QApplication application(argc, argv);
MyGlWindow myGlWindow;
myGlWindow.show();

return application.exec();

}

myglwindow.h

#ifndef MY_GL_WINDOW
#define MY_GL_WINDOW
#include <QtOpenGL\QGLWidget>
#include <QtCore\qtimer.h>

class MyGlWindow : public QGLWidget
{
Q_OBJECT

GLuint vertexBufferID;
QTimer myTimer;

protected:
void initializedGL();
void paintGL();
private slots:
void myUpdate();
};

#endif // !MY_GL_WINDOW

myglwindow.cpp
#include <GL\glew.h>
#include <cassert>
#include "myGlWindow.h"

void MyGlWindow::initializedGL()
{

GLenum errorCode = glewInit();
assert(errorCode == 0);

glGenBuffers(1, &vertexBufferID);
glBindBuffer(GL_ARRAY_BUFFER, vertexBufferID);

float verts[] =
{
	+0.0f, +0.1f,
	-0.1f, -0.1f,
	+0.1f, -0.1f
};

glBufferData(GL_ARRAY_BUFFER, sizeof(verts),
	verts, GL_STATIC_DRAW);

bool keepRunning = true;
while (keepRunning)
{
	myUpdate();
}

connect(&myTimer, SIGNAL(timeout()),
	this, SLOT(myUpdate()));
myTimer.start(0);

}

void MyGlWindow::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
glDrawArrays(GL_TRIANGLES, 0, 3);
}

void MyGlWindow::myUpdate()
{
}

SGaist

There's no need to re-build Qt for that, you can for the backend to use desktop OpenGL on Windows.

If you don't use any .pro file what are you using to manage your project ?

In any case, you have to link against the Qt 5 Widgets library.

MohsinM.

@SGaist said in linker errors for QWidget:

y .pro file what are you using to manage your project ?
In any case, you have to link against the

I'm using VS 2017 - 15.9.6

SGaist

Then add the Qt Widget module to the list of dependencies of your project.