C timer

ieatsplaydoh · 04-30-2007, 09:09 PM

I am an new C programmer, (yes i know its old), and i need some help with a basic program mainly using printf

ill use this example:

main()
{
printf("Programming is fun!")
printf("and Programming in C is more fun")
}

but, how do i make the terminal print out "Programming is fun!", then wait 5 seconds and print out "and Programming in C is more fun"?
i dont know if it matters, but i am using Linux

wjevans_7d1@yahoo.co · 04-30-2007, 09:37 PM

Type this at the command line:

Code:

man 3 sleep

Hope this helps.

taylor_venable · 05-01-2007, 09:33 AM

Since you're not (yet) a hacker extraordinaire, forget about this method until later:

You could also have the kernel send you a signal at the specified interval, as this code demonstrates.

Code:

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

static void handler(int); /* signal handler */

int main(int argc, char* argv[]) {
    int x = 0;
    /* register the handler for keyboard interrupt */
    if (signal(SIGINT, handler) == SIG_ERR)
        fprintf(stderr, "Couldn't handle SIGINT.\n");
    /* register the handler for alarm signal */
    if (signal(SIGALRM, handler) == SIG_ERR)
        fprintf(stderr, "Couldn't handle SIGALRM.\n");
    else
        /* set the alarm to go off in three seconds */
        alarm(3);
    while (1) {
        fprintf(stderr, "%d ", x++);
        sleep(1);
    }
    return 0;
}

static void handler(int signum) {
    if (signum == SIGINT) {
        printf("Got an interrupt signal.\n");
        exit(0);
    }
    else if (signum == SIGALRM) {
        fprintf(stderr, "ALARM! ");
        alarm(3);
    }
    return;
}

osor · 05-01-2007, 10:42 AM

Was that supposed to be a joke?

ieatsplaydoh · 05-01-2007, 05:27 PM

um...
what?
as osor said, is that supposed to be a joke.
i am using a very old C book from the 80's
i am still in the first chapter.
i dont understand ANY of that code you just put there.
anything simpler would be appreciated

tuxdev · 05-01-2007, 06:02 PM

I don't think you are supposed to understand that.. yet.

If you want to know what those syscalls are doing, I highly recommend getting "Advanced Programming for the Unix Enviroment". The author explains stuff far better than I would.

ieatsplaydoh · 05-01-2007, 08:38 PM

Quote:

Originally Posted by tuxdev

I don't think you are supposed to understand that.. yet.

If you want to know what those syscalls are doing, I highly recommend getting "Advanced Programming for the Unix Enviroment". The author explains stuff far better than I would.

thanks
ill get that from the library cause i can be a tightwad
i learned all i know about linux from the library too

osor · 05-01-2007, 09:03 PM

But you don’t need an expensive book to tell you that “sleep(5);” sleeps for 5 seconds (the original question)…

taylor_venable · 05-01-2007, 09:42 PM

Quote:

Originally Posted by osor

Was that supposed to be a joke?

Nah; at least, I didn't think it was a very funny one. A good one would have been if I'd written how to use the OCaml FFI to interact with C code that slept.

No, the OP already had his answer, so I described another (more flexible) way to solve the problem. I did preface it with a statement saying that he wouldn't understand it yet... just know that it's possible to have a function called recurrently inside your code according to a timer.

Evil, I know; sorry.

wjevans_7d1@yahoo.co · 05-02-2007, 06:07 AM

*ahem*

To unhijack this thread for just a sec (then you guys can get back to playing):

ieatsplaydoh, did

Code:

man 3 sleep

solve the problem for you?

knobby67 · 05-02-2007, 09:19 AM

use slpeep(3); between the two prinf's you'll also need #include <unistd.h> as a header for the sleep function so

#include<stdio.h>
#include <unistd.h>

main()
{
printf("Programming is fun!");
slpeep(3);
printf("and Programming in C is more fun");
}

kaz2100 · 05-02-2007, 10:31 AM

Hya,

I guess it would be a good idea to flush buffer by fflush(NULL); after printf("Programming is fun");

Code:

printf("Programming is fun");
fflush(NULL);
system("sleep 5");
printf("fun fun fun");

Happy Penguins!

ieatsplaydoh · 05-02-2007, 06:36 PM

Quote:

Originally Posted by wjevans_7d1@yahoo.co

*ahem*

To unhijack this thread for just a sec (then you guys can get back to playing):

ieatsplaydoh, did

Code:

man 3 sleep

solve the problem for you?

oops!
i saw that..
but for some reason i thought it was for bash and i ignored it.
oops...
maybe that'll work...
*checks*
yay! it works
thanks!