Reference original:

According to the 11th lecture of Visual Slam XIV, try to open sphere.g2o with g2o_viewer and find that it cannot be opened.

Checked a lot of information, found that it seems to be qt4 and qt5 conflict, there is still a dependency library installed before installing g2o, resulting in g2o_viewer no way to open normally. Because there are too many installed libraries, do not dare to uninstall qt4, so Just follow the link above and solve the problem.

The error message is:
g2o Error in `g2o_viewer’: realloc(): invalid pointer: 0x00007f6911493820
g2o_viewer has been abandoned (core dumped)

The system version is ubuntu16.04

The processing method is divided into 3 steps:

(1) Modify: Search FindQGLViewer and open it, add the followingBold code。

find_library(QGLVIEWER_LIBRARY_RELEASE
NAMES qglviewer-qt4 QGLViewer-qt4 qglviewer QGLViewer QGLViewer2
PATHS /usr/lib
/usr/local/lib
/usr/lib/x86_64-linux-gnu # Ubuntu 16.04 and derivatives
/opt/local/lib
/sw/lib

find_library(QGLVIEWER_LIBRARY_DEBUG
NAMES dqglviewer dQGLViewer dQGLViewer2 QGLViewerd2
PATHS /usr/lib
/usr/local/lib
/usr/lib/x86_64-linux-gnu # Ubuntu 16.04 and derivatives
/opt/local/lib
/sw/lib

(2) Install libqglviewer-dev-qt4.

sudo apt-get install libqglviewer-dev-qt4

(3) Clear the installed g2o, recompile and install g2o.

1 delete g2o

sudo rm -r /usr/local/lib/libg2o* /usr/local/include/g2o /usr/local/lib/g2o /usr/local/bin/g2o*

When uninstalling, the file may not be found in the terminal, but in fact, g2o has been uninstalled at this time.

2 empty g2o build folder
The build folder must be emptied, otherwise unintentional problems will occur when recompiling g2o.

3 recompile and install g2o
cmake…
make
sudo make install

This is OK, enter g2o_viewer sphere.g2o in the terminal, the long-lost g2o simulation pose is shown.