timer for getline() function

[RajendraNPTL]

hiii all
i want to read a string from commandline through getline() in c++. For that i want to add a timer of 5 sec. If no string read, then the program will terminate. can anybody know ?? I am using Centos 6.3
thanks

[suvarna271]

/* Wait 5 seconds. */
alarm(5);

/* getline */

/* Cancel alarm. */
alarm(0);

[weaknessforcats]

What are you trying to do? Wait 5 seconds for user input and then go ahead?

[Banfa]

getline can read from any input stream including cin

[weaknessforcats]

You're right. I'll edit my post.

[RajendraNPTL]

thnq suvarna.. it worked well.
But, at last it is giving one message "Alarm clock". How to suppress that one ??? and also if i want to do another task after 5 sec with exiting from program.. is this one also possible ??
-suvarna271

[RajendraNPTL]

-weaknessforcats
Exactly... but, not in wait. In that 5 sec time it needs to go to some other function and come back to the same getline(). Then with in 5 sec if i not entered any string, then again it has to got to that function and come back (looping)..
Main purpose is__ Timer for getline(), with in that time it needs to execute another function and come back .. any ideas ??
thanks

[weaknessforcats]

In that case you need to implement a multi-threaded program where your input is on a worker thread. That allows yur main thread to go elsewhere but also to return occasinally and inquire on the worker thread.

Not a beginner solution but multithreading is very common.

[RajendraNPTL]

thank you -weaknessforcats
i already got the solution using <pthreads>
Now, i dnt want to use that. is there any other way to solve the same problem ..?? Challenging one... !!

thanks

[donbock]

I don't believe this can be accomplished within the Standard C Library, but perhaps your implementation provides the necessary functions...

Do you have an input function that returns immediately with a success/failure status rather than blocking until the input is obtained? If so, then you can write your main function to do its main job and only occassionally check for input.

[RajendraNPTL]

-donbock
ha ha.. main problem is that only.. if i have a proper function to return immediately, i never go for threads and alarm and timers all these. okay you came to my point. Now give your ideas about immediate returning(atleast 2 sec) from getline() either with a success or failure .. ??
thanks

[weaknessforcats]

You will need to write your own input functions. Especially the one for the user input. All the standard functions wait indefinitely for the user to press the enter key. Your functon must only 2 secs for a keypress so you need to write your own input functions.

The standard input functions are just to get yoou started. Most applicatons of any size don't use them. Windows does not use them.