talk session

[Paul Falstad]

natha at hal.com (Nathaniel Ingersol) wrote:
>In article <1489 at cvbnetPrime.COM> mkaminsk at cvbnet.prime.com (mailhost) writes:
>:
>:Actually usleep(3) is going away in System V Release 4 (SVr4)
>:so you can use select(2):
>:
>:    #include <stdio.h>
>:    #include <sys/types.h>
>:    #include <sys/time.h>
>:
>:    struct timeval      timeout;
>:
>:    timeout.tv_sec = 0;
>:    timeout.tv_usec = number_of_microseconds;
>:
>:    /* call select for it's timeout feature */
>:    select(1, NULL, NULL, NULL, &timeout);
>:
>
>Am I missing something here, or why can't you just make a usleep out
>of setitimer?  You could even use ITIMER_REAL.

You could just do this, yes.

---
#include <sys/time.h>
#include <signal.h>
#include <stdio.h>

int handler(){;} /* needed to make pause() work */

usleep(unsigned usec) {
   struct itimerval ix;

   ix.it_value.tv_sec = 0;
   ix.it_value.tv_usec = usec;
   ix.it_interval.tv_sec = 0;
   ix.it_interval.tv_usec = 0;
   signal(SIGALRM,handler);
   setitimer(ITIMER_REAL,&ix,NULL);
   pause();
   signal(SIGALRM,SIG_DFL);
}
---

Looks harder to me.  :-)

--
              Paul Falstad  pfalstad at phoenix.princeton.edu
         And on the roads, too, vicious gangs of KEEP LEFT signs!
     If Princeton knew my opinions, they'd have expelled me long ago.