symbol could not be resolved

场景:eclipse+cygwin编译使报错:symbol 'NULL' could not be resolved解决方法

eclipse+cygwin编译使报错:symbol 'NULL' could not be resolved
同时报错的还有:tpye 'pthead_t' could not be resolved。
但是线程相关函数(如pthread_creat())却没有报错.请问为什么啊?

------解决方案--------------------
那你相关的头文件能#include么
------解决方案--------------------
贴所有代码 哦
------解决方案--------------------
或者加个#include <stddef.h>