c - 将有关信号的数据保存在文件中？

Question

我正在尝试将有关信号的某些信息保存在文件中，例如它在信号处理程序中被捕获的时间等。

void sig_handler(int signo){
   curr_signal = time(NULL);
   receivedtime[z] = curr_signal;
   signumber = signo;

   diff = curr_signal - receivedtime[z-1];
   z++;
   write(f, &diff, sizeof(diff));
}

我已经更新了我的程序以写入文件 (f)。我的问题是文件中没有写入任何内容。正在创建文件。

Answer 1

小心来自信号处理程序内部的调用。

来自 man 7 signal:

Async-signal-safe functions
   A signal handler function must be very careful, since processing  else‐
   where  may  be  interrupted at some arbitrary point in the execution of
   the program.  POSIX has the concept of "safe function".   If  a  signal
   interrupts  the  execution  of  an  unsafe function, and handler either
   calls an unsafe function [...],
   then the behavior of the program is undefined.

然后是异步信号安全的函数列表。

您的信号处理程序调用:

• time():好的，它是异步信号安全的
• fprintf():不，不是。