Timer In C

I just want to know whether anyone does know about the timer control in C, the problem is that when we use any input function like getchar(),getche() or even scanf(), then if user doesn't give the input, the program is suspended for infinite time. But is there a way to get out such that you give input only within 1 min (suppose) and if user is not giving input, the program continues with the execution of program taking user input as NULL. It may be real help for online based programs in C. Like in VB we have a Timer control which does that job. Does any guy know about it or any refrence that mentions it. Thanks For Your Patient Reading.

may be you can use kbhit()....

Code:

---


if( kbhit() )
{
    getchar/scanf/getch
}

---

this function is run if you push some button from your keyboard...
so if you don't push anything...
this function is not running.....

sory my english is not very good...
i hope you understand what i mean....

_kbhit() is non-standard and you must

Code:

---

#include <conio.h>

---

which is also a non-standard header.

Not sure what kind of input you want but

Code:

---

#include <conio.h>
#include <time.h>

int t = time(NULL);
char c;
while (time(NULL) - t < 60) {
    if (kbhit()) {
        putchar(c = getch());
        if (c == '\n')
            break;
    }
}

---

might be a start.

Hi!

Maybe it is irrelevant in the context but I used the time() function in one of my programs (which was web based) to calculate the typing speed of an individual for advanced security. The results were accurate. But keep in mind that in this case there are too many function calls for a single input in the worst case.

Regards,

Arun

Well, the best way of doing this is to use your OS internal timers. If you are using a UNIX based system you can use any one the ITIMER_* variables. Set the values of your ITIMER_* variables (say 1 min) . And at the begining of your program you can catch a signal raised from the OS upon the expiration of your timer. Your code should look like something below

Code:

---

int main() {
.....
struct itimerval sth;
....
....
signal(SIGALRM,SIG_DFL);
setitimer(sth....);
....
scanf()/fgets() whatever...
...
return o;
}

---

In Windows environmet you can also use such a mechanish (timers). You should check MSDN for detailed information if you use Windows as development environment.

Hi!

Nice solution. Hats off!

Regards,

Arun

Quote:

---

Originally Posted by OnionKnight

Not sure what kind of input you want but

Code:

---

#include <conio.h>
#include <time.h>

int t = time(NULL);
char c;
while (time(NULL) - t < 60) {
    if (kbhit()) {
        putchar(c = getch());
        if (c == '\n')
            break;
    }
}

---

might be a start.

---

There's a nice function called getche() that does exactly what this line does:
putch(getch());

Also with getch(), return on your key board gives a carriage return, not a new line. Control return gives a new line, I believe.

Furthermore, getch() return the character alpha when a non letter character is hit. A subsequent call to getch() would then return a letter character representing which character was hit.

The whole question is unanswerable unless unmeshghosh states the OS and compiler being used.

Thanks you all for paying such attention by the way the operating system i am talkin is Fedora Core 3 and compiler is gcc.

Scroll to the end
http://faq.cprogramming.com/cgi-bin/...&id=1043284385

Also, read up on termios as well, it will allow you to set timeouts as well.