flush stdin without blocking.

user@123 · 06-24-2014, 06:19 AM

Hello All,

Is there any way to clear stdin if it contains any character without blocking. I have tried fflush(stdin) but it did not work and i get to know its behavior is undefined and is not suitable for stdin. Can anyone tell any other way to flush stdin.

rtmistler · 06-24-2014, 06:41 AM

You could read it in either a tight loop or a loop with some form of yield such as nanosleep() with little or no time. I'm unsure if you invoke nanosleep() with zero time if it then allow for non-blocking, but at the very least you can put in just 1 nanosecond.

I'd make a function either inline or just a regular function which invoked nanosleep with zero time and read the stdin file handle until there was no more data coming from that handle; that would flush stdin.

user@123 · 06-24-2014, 06:47 AM

@rtmistler thanks for immediate reply but here i don't want to wait if stdin is not having any data. Execution of program should proceed further if stdin is empty without waiting for input to receive.

rtmistler · 06-24-2014, 07:06 AM

You can open the file descriptor and read it in non-blocking form.