C: Implicit declaration of function ‘read’ and ‘write’ ； did you mean ‘fwrite’?

1.

While working on an socket-based application, we received the following warnings from the compiler:

当在基于 socket 的应用工作时，我们接收到下面编译器发出的警告

implicit declaration of function 'read'
implicit declaration of function 'write'

read 和 write 是 声明在 unistd.h 头文件的函数，这是我们忘记了添加 #include <unistd.h> 的原因

#include <unistd.h>