password politic

Dear All,

 I am trying to configure the access to the postgreSQL server through web. I
would like that someone could give
a general idea of how the password politic works in PostgreSQL.

 Let me explain what I have tried so far.

 I want to do access to PostgreSQL using password encryption. What I have
read is that in that case you need to use
the passwd file.

 I tried to use the commands for adding a user to the system (create user or
createuser on the system prompt) but I have
seen that in that case, postgreSQL dont add a entry for the new user in the
passwd file. BUT if I use the command "pg_passwd passwd" and gives the
details for the new user, then it does add the entry to the passwd file, but
not in the pg_pwd file where stores the names of the users of postgreSQL (I
tried to access through the psql command to the database and the user doesnt
exist after only have added using pg_passwd).

 Does this mean that I have to do this two steps?. I am developing an
administration application under C++ Builder and I would like to add users
from that application using SQL, trigger, fuctions or whatever. How can I do
it without doing it manually?

 I hope I have explained myseft clearly.

 Thank you in advance and sorry for my English

 Miguel