ORB_SLAM2编译时执行 ./build_ros.sh 出现 error: ‘usleep’ was not declared in this scope

ORB_SLAM2编译时执行 ./build_ros.sh 出现 error: ‘usleep’ was not declared in this scope

如下图所示
ORB_SLAM2编译时执行 ./build_ros.sh 出现 error: ‘usleep’ was not declared in this scope
解决方法
跟据提示,在ORB_SLAM2/Examples/ROS/ORB_SLAM2/src/AR/ViewerAR.cc中加入头文件 #include<unistd.h>