catching signals while reading from pipe with select()

Question

using select() with pipe - this is what I am doing and now I need to catch SIGTERM on that. how can I do it? Do I have to do it when select() retur

Answer 1

You can call select() in a loop. This is known as restarting the system call. Here is some pseudo-C.

int retval = -1;
int select_errno = 0;

do {
   retval = select(...);

   if (retval < 0)
   {
       /* Cache the value of errno in case a system call is later
        * added prior to the loop guard (i.e., the while expression). */
       select_errno = errno;
   }

   /* Other system calls might be added here.  These could change the
    * value of errno, losing track of the error during the select(),
    * again this is the reason we cached the value.  (E.g, you might call
    * a log method which calls gettimeofday().) */

/* Automatically restart the system call if it was interrupted by
 * a signal -- with a while loop. */
} while ((retval < 0) && (select_errno == EINTR));

if (retval < 0) {
   /* Handle other errors here. See select man page. */
} else {
   /* Successful invocation of select(). */
}