EnvExample.cpp

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: EnvExample.cpp,v 12.1 2005/06/16 20:22:14 bostic Exp $
 */

#include <sys/types.h>

#include <errno.h>
#include <iostream>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <db_cxx.h>

using std::ostream;
using std::cout;
using std::cerr;

#ifdef macintosh
#define DATABASE_HOME   ":database"
#define CONFIG_DATA_DIR ":database"
#else
#ifdef DB_WIN32
#define DATABASE_HOME   "\\tmp\\database"
#define CONFIG_DATA_DIR "\\database\\files"
#else
#define DATABASE_HOME   "/tmp/database"
#define CONFIG_DATA_DIR "/database/files"
#endif
#endif

void    db_setup(const char *, const char *, ostream&);
void    db_teardown(const char *, const char *, ostream&);

const char *progname = "EnvExample";                    /* Program name. */

//
// An example of a program creating/configuring a Berkeley DB environment.
//
int
main(int, char **)
{
        //
        // Note: it may be easiest to put all Berkeley DB operations in a
        // try block, as seen here.  Alternatively, you can change the
        // ErrorModel in the DbEnv so that exceptions are never thrown
        // and check error returns from all methods.
        //
        try {
                const char *data_dir, *home;

                //
                // All of the shared database files live in /home/database,
                // but data files live in /database.
                //
                home = DATABASE_HOME;
                data_dir = CONFIG_DATA_DIR;

                cout << "Setup env\n";
                db_setup(home, data_dir, cerr);

                cout << "Teardown env\n";
                db_teardown(home, data_dir, cerr);
                return (EXIT_SUCCESS);
        }
        catch (DbException &dbe) {
                cerr << "EnvExample: " << dbe.what() << "\n";
                return (EXIT_FAILURE);
        }
}

// Note that any of the db calls can throw DbException
void
db_setup(const char *home, const char *data_dir, ostream& err_stream)
{
        //
        // Create an environment object and initialize it for error
        // reporting.
        //
        DbEnv *dbenv = new DbEnv(0);
        dbenv->set_error_stream(&err_stream);
        dbenv->set_errpfx(progname);

        //
        // We want to specify the shared memory buffer pool cachesize,
        // but everything else is the default.
        //
        dbenv->set_cachesize(0, 64 * 1024, 0);

        // Databases are in a subdirectory.
        (void)dbenv->set_data_dir(data_dir);

        // Open the environment with full transactional support.
        dbenv->open(home,
    DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN, 0);

        // Do something interesting...

        // Close the handle.
        dbenv->close(0);
}

void
db_teardown(const char *home, const char *data_dir, ostream& err_stream)
{
        // Remove the shared database regions.
        DbEnv *dbenv = new DbEnv(0);

        dbenv->set_error_stream(&err_stream);
        dbenv->set_errpfx(progname);

        (void)dbenv->set_data_dir(data_dir);
        dbenv->remove(home, 0);
        delete dbenv;
}

---