SEQUENCE primary key

Hello

 I have a question, if I have a table with a SEQUENCE primary key, that
obviously, I doesn't give in each new row inserted. For example if the
table locks:
  CREATE SEQUENCE id_seq;
  CREATE TABLE table (
    id    integer         DEFAULT nextval('id_seq')  CONSTRAINT table_id
PRIMARY KEY,
    arg1 integer,
    arg2 integer
  )

 How can I know which id receive each new row. I mean,

<http://ultralingua.com/onlinedictionary/index.html?action=define&ignoreaccents=on&wholewords=on&searchtype=stemming&text=sudden&service=english2spanish>

suddenly  I insert one row (*) with the arg1 and arg2 . So ...,  there
are something that I receive back ?? Some pointer, something? There are
any way to know which number receive my row ?

 Thank you,
   Gustavo

(*) This process can be multi-thread. In my case I use the libraries
with the wxWidget project with the class wxDbTable.