[Error] 'sort' was not declared in this scope

OpenCV——报错解决：error: ‘VideoCapture’ was not declared in this scope

error: ‘_swprintf’ was not declared in this scope 解决办法

安装fcgi时出现：error: ‘EOF’ was not declared in this scope解决方法

‘memset’ was not declared in this scope

错误解决办法：‘NULL’ was not declared in this scope

(OctreePointCloudChangeDetector运行错误)error: ‘Octree2BufBase’ was not declared in this scope #2564

Linux创建父子进程出现error: ‘fork‘ was not declared in this scope pid=fork()；

‘inet_pton’ was not declared in this scope

ros+arduino学习（踩坑）arduino error: ‘nullptr’ was not declared in this scope