Make File error while building g2o_viewer

[hkhanr]

Hi Sir, I wanted to run the openslam and for that I am compiling openslam_g2o library. However, after "cmake .." when run the "make" command, I get the following error and I am unable to resolve it.

Scanning dependencies of target g2o_simulator3d_application
[ 41%] Building CXX object g2o/apps/g2o_simulator/CMakeFiles/g2o_simulator3d_application.dir/test_simulator3d.cpp.o
[ 41%] Linking CXX executable ../../../../bin/g2o_simulator3d
[ 41%] Built target g2o_simulator3d_application
[ 41%] Generating moc_properties_widget.cxx
[ 42%] Generating ui_base_main_window.h
[ 42%] Generating ui_base_properties_widget.h
[ 43%] Generating moc_main_window.cxx
Scanning dependencies of target viewer_library
[ 44%] Building CXX object g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/g2o_qglviewer.cpp.o
/home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.cpp:46:13: error: conflicting return type specified for ‘virtual float g2o::{anonymous}::StandardCamera::zNear() const’
float zNear() const {
^
In file included from /usr/include/QGLViewer/qglviewer.h:26:0,
from /home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.h:22,
from /home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.cpp:19:
/usr/include/QGLViewer/camera.h:231:16: error: overriding ‘virtual qreal qglviewer::Camera::zNear() const’
virtual qreal zNear() const;
^
/home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.cpp:53:13: error: conflicting return type specified for ‘virtual float g2o::{anonymous}::StandardCamera::zFar() const’
float zFar() const
^
In file included from /usr/include/QGLViewer/qglviewer.h:26:0,
from /home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.h:22,
from /home/aquarius/openslam_g2o/g2o/apps/g2o_viewer/g2o_qglviewer.cpp:19:
/usr/include/QGLViewer/camera.h:232:16: error: overriding ‘virtual qreal qglviewer::Camera::zFar() const’
virtual qreal zFar() const;
^
g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/build.make:80: recipe for target 'g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/g2o_qglviewer.cpp.o' failed
make[2]: *** [g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/g2o_qglviewer.cpp.o] Error 1
CMakeFiles/Makefile2:610: recipe for target 'g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/all' failed
make[1]: *** [g2o/apps/g2o_viewer/CMakeFiles/viewer_library.dir/all] Error 2
Makefile:127: recipe for target 'all' failed
make: *** [all] Error 2
aquarius@aquarius-7G-Series:~/openslam_g2o/build$