This is mostly a shot in the dark, but have you tried removing the #defines and using const doubles? Ivan On Thu, Jul 14, 2011 at 4:49 AM, Steven Martin wrote: > Hi Guys, > > I am just trying to set the resolution in my Occupancy Grid message. > >    nav_msgs::OccupancyGrid costmap; >    costmap.info.resolution = 1.0; > > but I get this compile error > >  /src/costmap.cpp: In function ‘void chatterCallback(const sensor_msgs::LaserScan_ >::ConstPtr&)’: >  /src/costmap.cpp:19:18: error: expected unqualified-id before numeric constant >  /src/costmap.cpp:19:18: error: expected ‘;’ before numeric constant > > > Any ideas? One of the other students in the lab had a similar issue with setting "g" in a rgb colour message. "r" and "b" could set but "g" threw the same error. Interestingly both were Float32 message variables. > > > Steve > > ----------------------------------- > > #include "ros/ros.h" > #include "sensor_msgs/LaserScan.h" > #include "nav_msgs/OccupancyGrid.h" > #include "nav_msgs/MapMetaData.h" > > #include > #include > > #define resolution 0.5 > #define size 30  //+10m , -10m > const int length = size/resolution; > ros::Publisher costmap_pub; > > > void chatterCallback(const sensor_msgs::LaserScan::ConstPtr& msg) > { >    nav_msgs::OccupancyGrid costmap; >    costmap.data.resize(length*length,0); >    costmap.info.resolution = 1.0; >    costmap.info.width = length; >    costmap.info.height = length; >    costmap.header.stamp = ros::Time::now(); > >    float angle = msg->angle_min; >    int points = (int)(msg->angle_max - msg->angle_min)/msg->angle_increment; > > > .... > > > > > Steven Martin > steven.martin@qut.edu.au > > PhD Student > Queensland University of Technology > Gardens Point, S1107 > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >