-Wconversion warnings in melodic

[anja-sheppard]

I have the -Wconversion tag in my CMake (version 3.5), and it caught some warnings in ros/time.h. Nothing urgent, just wanted to pass it along in case you guys didn't compile with that flag. (Running ROS Melodic with gcc 7.4.0)

In file included from /opt/ros/melodic/include/ros/ros.h:38:0,
                 from /root/src/path_to_my_header.h:5,
                 from /root/src/path_to_my_test.cpp:2:
/opt/ros/melodic/include/ros/time.h: In instantiation of ‘T& ros::TimeBase<T, D>::fromSec(double) [with T = ros::Time; D = ros::Duration]’:
/opt/ros/melodic/include/ros/time.h:191:40:   required from here
/opt/ros/melodic/include/ros/time.h:161:11: warning: conversion to ‘uint32_t {aka unsigned int}’ from ‘long unsigned int’ may alter its value [-Wconversion]
       sec += (nsec / 1000000000ul);
       ~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/opt/ros/melodic/include/ros/time.h: In instantiation of ‘T& ros::TimeBase<T, D>::fromSec(double) [with T = ros::WallTime; D = ros::WallDuration]’:
/opt/ros/melodic/include/ros/time.h:247:44:   required from here
/opt/ros/melodic/include/ros/time.h:161:11: warning: conversion to ‘uint32_t {aka unsigned int}’ from ‘long unsigned int’ may alter its value [-Wconversion]
/opt/ros/melodic/include/ros/time.h: In instantiation of ‘T& ros::TimeBase<T, D>::fromSec(double) [with T = ros::SteadyTime; D = ros::WallDuration]’:
/opt/ros/melodic/include/ros/time.h:281:48:   required from here
/opt/ros/melodic/include/ros/time.h:161:11: warning: conversion to ‘uint32_t {aka unsigned int}’ from ‘long unsigned int’ may alter its value [-Wconversion]

[dirk-thomas]

Please try to compile the latest code from the kinetic-devel branch which includes #106. That will change the referenced lines already.

[anja-sheppard]

Can I do that even though I'm using ROS Melodic?

[dirk-thomas]

Yes, the kinetic-devel branch is the default / latest branch and is used for all ROS distro after Kinetic too.

[anja-sheppard]

Ok thanks! I didn't know that.

I built rostime, but how do I make sure that my code is using the built time.h and not whatever is in roscpp_core? Sorry for all of the questions.

[dirk-thomas]

If you build your code in the same workspace together with this repo it should use the headers from this branch. Hopefully the warning will be gone then. If they are still there please check the path of the header to ensure it is using the branch and not the one from the system package.

[anja-sheppard]

Excellent, thanks. Built with this repo branch kinetic-devel, but still got one warning:

In file included from /opt/ros/melodic/include/ros/publisher.h:34:0,
                 from /opt/ros/melodic/include/ros/node_handle.h:32,
                 from /opt/ros/melodic/include/ros/ros.h:45,
                 from /root/src/my_ros_ws/src/item_stream_service_server.cpp:2:
/root/src/my_ros_ws/src/roscpp_core/roscpp_serialization/include/ros/serialization.h: In instantiation of ‘void ros::serialization::deserializeMessage(const ros::SerializedMessage&, M&) [with M = item_server::RequestItemStreamRequest_<std::allocator<void> >]’:
/opt/ros/melodic/include/ros/service_callback_helper.h:176:28:   required from ‘bool ros::ServiceCallbackHelperT<Spec>::call(ros::ServiceCallbackHelperCallParams&) [with Spec = ros::ServiceSpec<item_server::RequestItemStreamRequest_<std::allocator<void> >, item_server::RequestItemStreamResponse_<std::allocator<void> > >]’
/root/src/my_ros_ws/src/item_server/src/item_stream_service_server.cpp:26:1:   required from here
/root/src/my_ros_ws/src/roscpp_core/roscpp_serialization/include/ros/serialization.h:859:42: warning: conversion to ‘uint32_t {aka unsigned int}’ from ‘long unsigned int’ may alter its value [-Wconversion]
   IStream s(m.message_start, m.num_bytes - (m.message_start - m.buf.get()));

[anja-sheppard]

Fixed the problem - I'll start a pull request.

[anja-sheppard]

@dirk-thomas Any update on this?

[dirk-thomas]

Thanks for the ping. I just merged the PR.