find out if NO keys are being pressed

[NotBash]

Using system() or terminal I can set the input mode to raw instead of cooked with "stty raw -echo" which lets me know if a key was pressed using getchar(), but I am still confused about how to find out if no key is currently being pressed. Any suggestions?
Preferably in C/C++, but bash would be fine too.

Thanks!

[BrianMicek]

Hi NotBash,
I'm confused by your post. Typically the way people determine if input is available is to select(2) or poll(2) in file descriptor 0. File descriptor 0 is #define'd in one of the standard headers as STDIN_FILENO. Cooked or raw terminal modes don't seem to apply here as far as I can see.

[Rubberman]

Well, if there is NO event, there is NO event... IE, no key press, then there is no key press... If you want to know if there is no key press for some period, then select() with a timeout will do the job nicely. If you want to know that there is no key press currently, then you can assume that if you are not in an event handler, there is no key press active...

[drl]

Hi.

In bash, there is a time-out feature for the read command. That suggests that within a given time frame no key would have been pressed. See man bash for details:

read: read [-ers] [-u fd] [-t timeout] [-p prompt] [-a array] [-n nchars] [-d delim] [name ...]
    One line is read from the standard input ...
excerpt from man bash

Best wishes ... cheers, drl

[Rubberman]

Thanks drl. I wasn't aware of the read -t timeout option for bash scripts (never needed it before). Good call! Only issue is that this is to read a line, until when an EOL or ^D are issued. I think that the poster is looking for ANY key press. At least it is useful to know.