qt - undefined reference to `_imp__Z*' - c++

Question

Good day all
Please note: C++ newbie here
I am creating shared libraries among various other c++ features to allow for a complete understanding, however I am at a loss.
Problem:
As the title suggests, a list of errors:
I have no idea what causes them, and googling does not provide much insight either. As suggested here to add the Q_Object macro, I have done so but obviously it is of no use.
Various other SO posts suggest checking the correct header, etc which is correct.
Error:
netm.cpp:3: error: undefined reference to `vtable for netm'
netm.cpp:3: error: undefined reference to `_imp___ZN4miscC1Ev'
netm.cpp:6: error: undefined reference to `vtable for netm'
netm.cpp:6: error: undefined reference to `_imp___ZN4miscC1Ev'
//...
I have several more errors similar to these above, but solving these should assist me in resolving the rest
From all the tutorials, etc I have followed, I have done nothing out of the ordinary.
Note: I am unsure what information is all required, if more is required, I'll gladly share.
//.pro
QT -= gui
QT += network
TARGET = netm
TEMPLATE = lib
DEFINES += NETM_LIBRARY
SOURCES += netm.cpp
HEADERS += netm.h\
netm_global.h
unix {
target.path = /usr/lib
INSTALLS += target
}
//netm_global.h - FULL
#ifndef NETM_GLOBAL_H
#define NETM_GLOBAL_H
#include <QtCore/qglobal.h>
#if defined(NETM_LIBRARY)
# define NETMSHARED_EXPORT Q_DECL_EXPORT
#else
# define NETMSHARED_EXPORT Q_DECL_IMPORT
#endif
#endif // NETM_GLOBAL_H
//netm.h - FULL
#ifndef NETM_H
#define NETM_H
#include "netm_global.h"
#include "../misc/misc.h"
#include "../gen/gen.h"
#include <QHostInfo>
#include <QTcpSocket>
class NETMSHARED_EXPORT netm
{
Q_OBJECT
public:
netm();
netm(QString hostname);
bool Send(int portNumber, char* message = NULL);
ReturnObject read();
bool isServerOnline(QString IP = QString());
int getPing(QString IP = QString());
void getIP();
void disconnectFromServer();
~netm();
private slots:
void getIP();
private:
misc m;
QHostInfo serverInfo;
QHostAddress serverIP;
QTcpSocket tcp_con;
};
#endif // NETM_H
//netm.cpp - Partial
#include "netm.h"
netm::netm(){ <--- ERROR line
}
netm::netm(QString hostname) <--- ERROR line
{
serverInfo.lookupHost(hostname, 0, SLOT(getIP()));
}
//...
Help (with explanations) would be greatly appreciated!
UPDATE
As suggested, I defined the constructor in misc.cpp, since it was not present.
Recompiling, I read an error mentioning that the netm class needed to inherit from QObject.
Thus adding/changing:
//netm.h - Partial
#include //...
#include <QObject>
class NETMSHARED_EXPORT netm : public QObject
{
Q_OBJECT
public:
netm();
netm(QString hostname);
//...
};
Errors persist:
netm.cpp:3: error: undefined reference to `_imp___ZN4miscC1Ev'
netm.cpp:3: error: undefined reference to `_imp___ZN4miscD1Ev'
netm.cpp:6: error: undefined reference to `_imp___ZN4miscC1Ev'
netm.cpp:6: error: undefined reference to `_imp___ZN4miscD1Ev'
For completeness sake (misc is also a dynamic library):
//misc.h
#ifndef MISC_H
#define MISC_H
#include "misc_global.h"
#include <QString>
#include <QList>
class MISCSHARED_EXPORT misc
{
public:
misc();
~misc();
//String Literals
//Network related
static QString googleDNS;
//Command Codes
static QString CMD_AUTH;
static QString CMD_REQ;
//Request Codes
static QString REQ_USER_INFO;
static QString REQ_VPN_DATA;
static QString REQ_VPN_UP;
//...
};
//misc.cpp
#include "misc.h"
misc::misc(){
//Network related
QString googleDNS = QStringLiteral("8.8.8.8");
//Command Codes
QString CMD_AUTH = QStringLiteral("AUTH");
QString CMD_REQ = QStringLiteral("REQ");
//Request Codes
QString REQ_USER_INFO = QStringLiteral("USER_INFO");
QString REQ_VPN_DATA = QStringLiteral("VPN_DATA");
QString REQ_VPN_UP = QStringLiteral("VPN_UP");
}
misc::~misc(){}
As seen here, the constructor exists,
any other thoughts?

Answer 1

Missing calls to _imp___ZN4miscC1Ev, which is misc::misc() according to c++filt, likely means that the class misc is missing a defined default constructor. Check to make sure you're compiling in a definition for misc::misc().
For the vtable error, make sure that you've provided a definition (even if empty or stubbed out) for every function declared in netm (or at minimum all of the virtual functions in netm). The vtable for a class references every virtual function, so all of the virtual functions must be defined or it will not compile.