Compiling Qt Plugin with CMake issue

[postb99]

Hello,

I am switching my .pro project to CMake.

It's a Qt 4 custom plugin.

For now it doesn't build, it complains here: "undefined interface" where I do Q_INTERFACES...

#include <QObject>
#include "XAppletPlugin.h"
#include "XApplet.h"
 
namespace tutorial1 {
/**
 * @brief AppletTutorial1 plugin class
 */
class APPLETTUTORIAL1SHARED_EXPORT AppletTutorial1 : public QObject, public XAppletPlugin
{
    // Q_OBJECT macro should appear in any class derived from QObject
    Q_OBJECT
    // Q_INTERFACES should appear in any class derived from a given interface
    Q_INTERFACES(XAppletPlugin)

#include <QObject>
#include "XAppletPlugin.h"
#include "XApplet.h"

namespace tutorial1 {
/**
 * @brief AppletTutorial1 plugin class
 */
class APPLETTUTORIAL1SHARED_EXPORT AppletTutorial1 : public QObject, public XAppletPlugin
{
    // Q_OBJECT macro should appear in any class derived from QObject
    Q_OBJECT
    // Q_INTERFACES should appear in any class derived from a given interface
    Q_INTERFACES(XAppletPlugin)

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"XAppletPlugin.h" is correctly found and include isn't in error, only "Q_INTERFACES" line If I hover with the mouse on include lines at top I see the full path of file as tooltip and it's OK: "C:\myExternalLib\relWithDebInfo\include\conta iner-data\XAppletPlugin.h"

So here is my CMakeLists:

cmake_minimum_required(VERSION 2.8.8)
 
project(applettutorial1)
 
FIND_PACKAGE(Qt4 REQUIRED)
 
# application headers files
SET(applettutorial1_HEADERS
    "include/applettutorial1.h"
    "include/applet-tutorial1_global.h"
    "include/applettutorial1imp.h"
)
# application files: source and headers again
# so that they show up in project files tree
SET(applettutorial1_SOURCES 
    ${applettutorial1_HEADERS}
    src/applettutorial1.cpp
    src/applettutorial1imp.cpp
    tutorial1.xml
)
 
MESSAGE(STATUS "Source files: " ${applettutorial1_SOURCES} )
 
# Required
QT4_WRAP_CPP(applettutorial1_HEADERS_MOC ${applettutorial1_HEADERS})
 
# SET(applettutorial1_RESOURCES images.qrc)
#QT4_ADD_RESOURCES(applettutorial1_RESOURCES_RCC ${applettutorial1_RESOURCES})
 
if (QT4_FOUND)
#   SET(QT_USE_QTDESIGNER ON)
    INCLUDE(${QT_USE_FILE})
    ADD_DEFINITIONS(${QT_DEFINITIONS})
else()
    message(FATAL_ERROR "No Qt4 found")
endif()
 
IF(CMAKE_BUILD_TYPE MATCHES DEBUG)
    SET(EXTERNALLIB_BASE "$ENV{EXTERNALLIB}/debug")
ELSE()
    SET(EXTERNALLIB_BASE "$ENV{EXTERNALLIB}/relWithDebInfo")
ENDIF()
 
MESSAGE(STATUS "EXTERNALLIB base dir: " ${EXTERNALLIB_BASE} )
 
 
# EXTERNALLIB version
SET(VERSION "0.24.0")
 
# EXTERNALLIB includes
include_directories(
"${CMAKE_CURRENT_SOURCE_DIR}/include"
"${EXTERNALLIB_BASE}/include"
"${EXTERNALLIB_BASE}/include/container-data"
)
 
link_directories("${EXTERNALLIB_BASE}/lib")
 
# executable then list of files
add_executable(
    applettutorial1
    ${applettutorial1_SOURCES}
    ${applettutorial1_HEADERS_MOC}
   # ${applettutorial1_RESOURCES_RCC}
)
 
target_link_libraries(
    applettutorial1
    ${QT_LIBRARIES}
    container-data
)

cmake_minimum_required(VERSION 2.8.8)

project(applettutorial1)

FIND_PACKAGE(Qt4 REQUIRED)

# application headers files
SET(applettutorial1_HEADERS
    "include/applettutorial1.h"
    "include/applet-tutorial1_global.h"
    "include/applettutorial1imp.h"
)
# application files: source and headers again
# so that they show up in project files tree
SET(applettutorial1_SOURCES 
    ${applettutorial1_HEADERS}
    src/applettutorial1.cpp
    src/applettutorial1imp.cpp
    tutorial1.xml
)

MESSAGE(STATUS "Source files: " ${applettutorial1_SOURCES} )

# Required
QT4_WRAP_CPP(applettutorial1_HEADERS_MOC ${applettutorial1_HEADERS})

# SET(applettutorial1_RESOURCES images.qrc)
#QT4_ADD_RESOURCES(applettutorial1_RESOURCES_RCC ${applettutorial1_RESOURCES})

if (QT4_FOUND)
#   SET(QT_USE_QTDESIGNER ON)
    INCLUDE(${QT_USE_FILE})
    ADD_DEFINITIONS(${QT_DEFINITIONS})
else()
    message(FATAL_ERROR "No Qt4 found")
endif()

IF(CMAKE_BUILD_TYPE MATCHES DEBUG)
    SET(EXTERNALLIB_BASE "$ENV{EXTERNALLIB}/debug")
ELSE()
    SET(EXTERNALLIB_BASE "$ENV{EXTERNALLIB}/relWithDebInfo")
ENDIF()

MESSAGE(STATUS "EXTERNALLIB base dir: " ${EXTERNALLIB_BASE} )


# EXTERNALLIB version
SET(VERSION "0.24.0")

# EXTERNALLIB includes
include_directories(
"${CMAKE_CURRENT_SOURCE_DIR}/include"
"${EXTERNALLIB_BASE}/include"
"${EXTERNALLIB_BASE}/include/container-data"
)

link_directories("${EXTERNALLIB_BASE}/lib")

# executable then list of files
add_executable(
    applettutorial1
    ${applettutorial1_SOURCES}
    ${applettutorial1_HEADERS_MOC}
   # ${applettutorial1_RESOURCES_RCC}
)

target_link_libraries(
    applettutorial1
    ${QT_LIBRARIES}
    container-data
)

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In my code there is no "Q_EXPORT_PLUGIN2" because this is managed by the external lib I use, which acts as a plugin host.

Thanks,

---

Added after 1 9 minutes:

I've changed "add_executable" to the following but I didn't solve the error for now.

# name, type then list of files
add_library(
    applettutorial1 SHARED
    ${applettutorial1_SOURCES}
    ${applettutorial1_HEADERS_MOC}
   # ${applettutorial1_RESOURCES_RCC}
)

# name, type then list of files
add_library(
    applettutorial1 SHARED
    ${applettutorial1_SOURCES}
    ${applettutorial1_HEADERS_MOC}
   # ${applettutorial1_RESOURCES_RCC}
)

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[postb99]

Better use:

SET (CMAKE_AUTOMOC ON)

SET (CMAKE_AUTOMOC ON)

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rather than old way of using:

QT4_WRAP_CPP

QT4_WRAP_CPP

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But then I still have linkage errors:

applettutorial1.cpp.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) const tutorial1::AppletTutorial1::`vftable'{for `XAppletPlugin'}" (__imp_??_7AppletTutorial1@tutorial1@@6BXAppletPlugin@@@) referenced in function "public: __cdecl tutorial1::AppletTutorial1::AppletTutorial1(void)" (??0AppletTutorial1@tutorial1@@QEAA@XZ)

applettutorial1.cpp.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) const tutorial1::AppletTutorial1::`vftable'{for `XAppletPlugin'}" (__imp_??_7AppletTutorial1@tutorial1@@6BXAppletPlugin@@@) referenced in function "public: __cdecl tutorial1::AppletTutorial1::AppletTutorial1(void)" (??0AppletTutorial1@tutorial1@@QEAA@XZ)

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Any way to change thread title to "Compiling Qt Plugin with CMake issue" ? I cannot edit my thread base post anymore...

---

Added after 55 minutes:

Solved by including the right headers (there was a check against CMAKE_BUILD_TYPE) and building as STATIC instead of SHARED.