[ros-users] manifest.xml msg export

[Joel Cartwright]

Hi,

For modules that export messages, I'm a little confused by the use of 
this block in manifest.xml as suggested by
http://www.ros.org/wiki/ROS/Tutorials/DefiningCustomMessages:

<export>
   <cpp cflags="-I${prefix}/msg/cpp"/>
</export>

That directory doesn't seem to exist after rosmake; the auto-generated 
C++ code is placed under msg_gen instead.

When loading projects for dependant modules into eclipse (following the 
relevant ROS wiki page), eclipse gives a warning about non-existent 
include directories due to this block. An include line to the correct 
path is also added to the eclipse .cproject file, so the build works anyway.

What purpose does this export block have? Java, lisp and octave code is 
generated uner /msg - is the intention to move the cpp code under /msg 
at some point, and this is designed to allow that?

Thanks,

Joel
-- 
Research Assistant
Ocean Systems Laboratory
Heriot-Watt University, UK