Thanks for replying.
I tried the sites mentioned by you. But they don't show the sources. I have come across a source that could toggle caps lock on and off but on a Windows/Dos operating system using POKEB or PEEKB functions including in header file DOS.H, which is not helpful, as I have to run the program on a Unix (SCO Unixware) Operating system on which dos.h cannot be run. Can you or any one suggest what functions are available on Unix Operating system like POKEB or PEEKB on Windows/Dos operating system. :p