Berkeley DB

Opening the Databases

Next, we open three databases (“color,” “fruit,” and “cats”) in the database environment. Again, our DB database handles are declared to be free-threaded using the DB_THREAD flag, and so may be used by any number of threads we subsequently create.

int 
main(int argc, char *argv) 
{
       extern char *optarg; 
       extern int optind; 
       DB *db_cats, *db_color, *db_fruit; 
       DB_ENV *dbenv; 
       pthread_t ptid; 
       int ch; 

       while ((ch = getopt(argc, argv, "")) != EOF) 
               switch (ch) {
               case '?': 
               default: 
                       usage(); 
               } 
       argc -= optind; 
       argv += optind; 
       env_dir_create(); 
       env_open(&dbenv); 

       /* Open database: Key is fruit class; Data is specific type. */
						db_open(dbenv, &db_fruit, "fruit", 0);
						/* Open database: Key is a color; Data is an integer. */
						db_open(dbenv, &db_color, ...