EINTR — the function was interrupted by a signal, which was caught by a signal handler in the program, and the signal handler returned normally.
程序中的信号处理程序捕获到函数的执行被某个信号中断，信号处理程序然后按正常方式返回。
2
When a signal that is being caught is handled by a process, the normal sequence of instructions being executed by the process is temporarily interrupted by the signal handler.
当进程处理所捕获的信号时，正在执行的正常指令序列就会被信号处理器临时中断。
3
Your write system call will be interrupted by the bus error signal SIGBUS, because you performed a bad memory access.