we need to work with RL-RTX (RTOS) in our project. In this case, we have to make some web pages. We have experience building web pages on Linux using a "good web server".
can we code in c language and save this executable in .cgi extension and call from browser?
Yes, you can. Almost all web servers can be configured to serve cgi. You can use something like libcgi to handle the interface in your c code. However, it would probably be more efficient to use some sort of scripting language rather than c.