Debug ros node with GDB

Abstract

Debug the ros node with GDB. Some error (such as segment fault) is difficult to find. The GDB is a good choice to debug it.

Step 1: compile the ros package
```
$ catkin_make -DCMAKE_BUILD_TYPE=Debug
```

Step 2: run the ros node you want to debug with specified format ros node

$ rosrun --prefix 'gdb -ex run --args'  package   node

or (launch)

$ <node pkg="package" type="node" name="node_name" output="screen" launch-prefix="gdb -ex run --args" >/>

or (python)

launch-prefix="xterm -e python -m pdb "

commands	functions
bt	show location of error, e.g. segment fault
info files	show the detail information of the debugged file
info var	show all the global and static variables
info local	show all the local variables
More	Link, book