I am looking at the code which has the following:

read(conf_fd,conf,100);

Can someone tell me what these parameters are passed to read function?

Lookup the documentation of the read function.
We can only guess that
conf_fd may be a destination data buffer
conf maybe the source data buffer
100 is the number of bytes of data that should be read from conf to conf_fd.

I read the doc on read, but read only takes two arguments not three in this case.

Then it maybe a function provided by a custom made library. Don't you have at least the definition of that function? Usually the header file must have some kind of comment about the function.

Also, you don't have to announce you're a newbie with every thread title. Just title the questions with good titles like you have been doing.