何时检查EINTR并重复功能调用？

Question

我正在为嵌入式Linux系统编写用户应用程序,我正在使用常用功能,如open,close,read,ioctl等设备.现在,我读到了有关EINTR的信息,表明该功能被信号中断,但我不确定其含义.在我所有的示例程序中,有时它已完成,例如ioctl(),有时它没有完成,例如read().所以,我有点困惑.

我什么时候最好检查EINTR并重复功能调用？

Answer 1

请参阅sigaction:http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaction.html

SA_RESTART
  This flag affects the behavior of interruptible functions; that is, those 
  specified to fail with errno set to EINTR. If set, and a function specified 
  as interruptible is interrupted by this signal, the function shall restart 
  and shall not fail with EINTR unless otherwise specified. If the flag is not 
  set, interruptible functions interrupted by this signal shall fail with errno 
  set to EINTR.

默认情况下,您具有SA_RESTART行为,因此如果不使用信号,则不必担心EINTR.