Problem with signal handler and interrupted system call
Hi,
I have a daq program that runs in an infinite loop until it receives SIGINT. A handler catches the signal and sets a flag to stop the while loop. After the loop some things have to be cleaned up.
The problem is that I want my main while loop to wait until the next full second begins, to start some action. To do so it waits for the RTC interrupt. Unfortunately the read() which waits for the interrupt seems to be interrupted itself by SIGINT. That causes my program to exit abnormally with
and without cleaning up.
I already tried it with SIGHUP and SIGUSR1 instead of SIGINT without succes.
How could I prevent my read() from being interrupted?
Thanks in advance
Here are the important code snippets:
the loop in main()
the wait_for_the_interrupt function
That's your problem, more or less. If read() is interrupted by a system call, it returns -1, sets errno to EINTR. Your program itself does the perror and exiting, not read(). So just check if the return is -1 and errno != EINTR and restart the loop (for instance). You'll have to handle the logic for the ioctls and what not, too, or every now and then, your signal will interrupt the ioctl and exit.
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