[Documentation] [TitleIndex] [WordIndex

Note: This tutorial assumes that you have completed the previous tutorials: Using rxconsole and roslaunch.
(!) Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags.

How to Roslaunch Nodes in Valgrind or GDB

Description: When debugging roscpp nodes that you are launching with roslaunch, you may wish to launch the node in a debugging program like gdb or valgrind instead. Doing this is very simple.

Keywords: roslaunch, valgrind, gdb, pdb

Tutorial Level: INTERMEDIATE

Next Tutorial: Profiling roslaunch nodes

The launch-prefix attribute of the <node> tag that, among other things, makes it easy to debug a ROS node process. Here are some example launch-prefixes you might find useful:

Obtaining core dumps

To obtain core dumps when processes crash, first set the core file size limit. To check the limits, run:

$ ulimit -a
core file size          (blocks, -c) 0           #  <-- Prevents core dumps
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 20
file size               (blocks, -f) unlimited
pending signals                 (-i) 16382
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) unlimited
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

Set the core size to unlimited:

ulimit -c unlimited

Now crashing processes will attempt to create core files. Currently (2010-07-02) they will fail to create the file because the default roslaunch working directory, $ROS_HOME, contains a directory named "core". This directory prevents the core dump from being created.

To allow core dumps to be created, set the core filename to use the process pid by default. Run the following as root:

echo 1 > /proc/sys/kernel/core_uses_pid

Now core dumps will show up as $ROS_HOME/core.PID

Error shooting

[tcsetpgrp failed in terminal_inferior: Inappropriate ioctl for device]

2020-03-28 13:06