I have an 'inkey' in a function.
If I wish to cancel this function, the cancel works but the system stilll waits for the 'inkey' response.
I have tried 'send_string' but without success.
Any ideas please?

From the manual
inkey_active = 0; // terminate inkey instruction

Thanks evilsob. Much appreciated.
Excellent tip.
Alas this project begun in 5.24, I came across it, decided to finish it, but couldn't be bothered to upgrade.
There is a work-around, but it is not as elegant or easy as 'inkey'
If needs be, I'll upgrade (but a lot of WDL = but at least now I know what to do if I wasn't so lazy) - or any other ideas please.

Another thing you could do with with EvilSOB's answer:

Let's say we've got multiple text boxes that a user could click on and type things.

When they click on a box, make the first command inkey_active = 0; You could also use OFF. Then it activates inkey for that box. Why? Because the user might already have inkey active for something else, and it must be terminated. So don't forget to keep that in mind. I created quite a few bugs by not doing that before.