Compiler warnings with arrays

OS: Ubuntu 22.04 g++

$ g++ --version
g++ (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Message: ROS2 tf2_msgs/msg/TFMessage in Humble

$ ros2 interface show tf2_msgs/msg/TFMessage 
geometry_msgs/TransformStamped[] transforms
    #
    #
    std_msgs/Header header
        builtin_interfaces/Time stamp
            int32 sec
            uint32 nanosec
        string frame_id
    string child_frame_id
    Transform transform
        Vector3 translation
            float64 x
            float64 y
            float64 z
        Quaternion rotation
            float64 x 0
            float64 y 0
            float64 z 0
            float64 w 1

IDL:

$ find /opt/ros/humble | grep TFMessage.idl | xargs cat
// generated from rosidl_adapter/resource/msg.idl.em
// with input from tf2_msgs/msg/TFMessage.msg
// generated code does not contain a copyright notice

#include "geometry_msgs/msg/TransformStamped.idl"

module tf2_msgs {
  module msg {
    struct TFMessage {
      sequence<geometry_msgs::msg::TransformStamped> transforms;
    };
  };
};

When compiling it with g++ with -Wall, -Wpedantic, I get the following warning.

libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c: In function ‘tf2_msgs_msg_TFMessage_serialize_topic’:
libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c:32:26: warning: comparison of integer expressions of different signedness: ‘int’ and ‘uint32_t’ {aka ‘unsigned int’} [-Wsign-compare]
   32 |         for(int i = 0; i < topic->transforms_size; ++i)
      |                          ^
libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c: In function ‘tf2_msgs_msg_TFMessage_deserialize_topic’:
libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c:50:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘uint32_t’ {aka ‘unsigned int’} [-Wsign-compare]
   50 |             for(int i = 0; i < topic->transforms_size; ++i)
      |                              ^
libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c: In function ‘tf2_msgs_msg_TFMessage_size_of_topic’:
libraries/AP_DDS/generated/tf2_msgs/msg/TFMessage.c:62:26: warning: comparison of integer expressions of different signedness: ‘int’ and ‘uint32_t’ {aka ‘unsigned int’} [-Wsign-compare]
   62 |         for(int i = 0; i < topic->transforms_size; ++i)

This is preventing me from using -Werr in my build.

For the for loops, perhaps use a uint32_t or a size_t type?

// Copyright 2016 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/*!
 * @file TFMessage.h
 * This header file contains the declaration of the described types in the IDL file.
 *
 * This file was generated by the tool gen.
 */

#ifndef _TFMessage_H_
#define _TFMessage_H_

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdint.h>
#include <stdbool.h>
#include "geometry_msgs/msg/TransformStamped.h"

typedef struct tf2_msgs_msg_TFMessage
{
    uint32_t transforms_size;
    geometry_msgs_msg_TransformStamped transforms[100];
} tf2_msgs_msg_TFMessage;

struct ucdrBuffer;

bool tf2_msgs_msg_TFMessage_serialize_topic(struct ucdrBuffer* writer, const tf2_msgs_msg_TFMessage* topic);
bool tf2_msgs_msg_TFMessage_deserialize_topic(struct ucdrBuffer* reader, tf2_msgs_msg_TFMessage* topic);
uint32_t tf2_msgs_msg_TFMessage_size_of_topic(const tf2_msgs_msg_TFMessage* topic, uint32_t size);

#ifdef __cplusplus
}
#endif

#endif // _TFMessage_H_

eProsima / Micro-XRCE-DDS-Gen

Compiler warnings with arrays #63