Please give me a help.

Dear sir:
Following is one part of program to connect to postgresql server.
const char* conninfo="host=192.168.8.2 port=5432" database=log  username=tom password=xxx;   PgDatabase pgdb(conninfo);
     if (pgdb.ConnectionDb()){        printf("connection server error!");       exit(0); }       printf("connection
serverok.");
 

When compile it ,
Always appears "request for member connectiondb in pgdb ,which is of non-aggregate pgdatabase . 
Thank you for your help.
Jason