Re: [9fans] Tread and alarm

[erik quanstrom]

> The client is (really?) suspended until Tread, but the read() sys call 
> cannot be interrupted by alarm().

i didn't understand your errata, so to clarify,
read(2) is interruptable with a note (modulo the
file server, but that's a different story).  here's a 
program that demonstrates:

; 8.readalarm
note: alarm
read -1
        interrupted

- erik

----

#include <u.h>
#include <libc.h>

void
nofun(void*, char *msg)
{
        print("note: %s\n", msg);
        if(strstr(msg, "alarm") != nil)
                noted(NCONT);
        else
                noted(NDFLT);
}

void
main(void)
{
        char buf[1024];
        int fd, n;

        fd = open("/net/log", OREAD);
        if(fd == -1)
                sysfatal("open: %r");
        notify(nofun);
        alarm(500);
        n = read(fd, buf, 1024);
        alarm(0);

        print("read %d\n", n);
        if(n < 0)
                print(" %r\n");
        exits("");
}