/** * apr tutorial sample code * http://dev.ariel-networks.com/apr/ */#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <stdio.h>#include <stdlib.h>#include <assert.h>#include <apr_general.h>#include <apr_dbm.h>#define MY_KEY1       "first-key"#define MY_VAL1       "first-val"static int do_store(apr_dbm_t *db);static int do_fetch(apr_dbm_t *db);static int do_iterate(apr_dbm_t *db);static int do_delete(apr_dbm_t *db);/** * dbm sample code * @remark Error checks omitted */int main(int argc, const char *argv[]){    apr_status_t rv;    apr_pool_t *mp;    apr_dbm_t *db;    const char *dbname;            if (argc < 2) {        printf("usage %s dbname\n", argv[0]);        return -1;    }    dbname = argv[1];    apr_initialize();    apr_pool_create(&mp, NULL);    if ((rv = apr_dbm_open(&db, dbname, APR_DBM_RWCREATE, APR_OS_DEFAULT, mp)) != APR_SUCCESS) {        goto error;    }    do_store(db);    do_fetch(db);    do_iterate(db);    do_delete(db);        apr_dbm_close(db);    apr_terminate();    return 0; error:    {        char errbuf[256];        apr_strerror(rv, errbuf, sizeof(errbuf));        printf("error: %d, %s\n", rv, errbuf);    }    apr_terminate();    return -1;}/** * Store an element(key-value pair) to dbm * @return TRUE if success, otherwise FALSE. */static int do_store(apr_dbm_t *db){    apr_status_t rv;    apr_datum_t key;    apr_datum_t val;    char *vstr;        /* apr_datum_t::dptr will be duplicated in apr_dbm_store() */    key.dptr = MY_KEY1;    key.dsize = sizeof(MY_KEY1);/* In this example, the size includes the last '\0' byte */    vstr = strdup(MY_VAL1);    val.dptr = vstr;    val.dsize = strlen(vstr) + 1;/* The size includes the last '\0' byte, again. This is often useful */    if ((rv = apr_dbm_store(db, key, val)) != APR_SUCCESS) {        return FALSE;    }    /* Since apr_datum_t::dptr was duplicated in apr_dbm_store(), we can free(3) this*/    free(vstr);    return TRUE;}/** * Fetch an element(key-value pair) from dbm by a key * @return TRUE if success, otherwise FALSE. */static int do_fetch(apr_dbm_t *db){    apr_status_t rv;    int ret;    apr_datum_t key;    apr_datum_t rval;    key.dptr = MY_KEY1;    key.dsize = sizeof(MY_KEY1);    /* Unlike other APIs, apr_dbm_exists() return TRUE or FALSE instead of apr_status_t */    ret = apr_dbm_exists(db, key);    printf("exists = %s\n", ret ? "yes" : "no");        if ((rv = apr_dbm_fetch(db, key, &rval)) != APR_SUCCESS) {        return FALSE;    }    printf("fetched value: %s, size=%d\n", rval.dptr, rval.dsize);    return TRUE;}/** * Iterate on the dbm * @return TRUE if success, otherwise FALSE. */static int do_iterate(apr_dbm_t *db){    apr_status_t rv;    apr_datum_t rkey;    apr_datum_t rval;        if ((rv = apr_dbm_firstkey(db, &rkey)) != APR_SUCCESS) {        return FALSE;    }    printf("first key: %s\n", rkey.dptr);        do {        if ((rv = apr_dbm_fetch(db, rkey, &rval)) != APR_SUCCESS) {            return FALSE;        }        printf("fetched key: %s, size=%d\n", rkey.dptr, rkey.dsize);        printf("fetched value: %s, size=%d\n", rval.dptr, rval.dsize);                if ((rv = apr_dbm_nextkey(db, &rkey)) != APR_SUCCESS) {            return FALSE;        }    } while (rkey.dptr);    return TRUE;}/** * Delete an element(key-value pair) from dbm by a key * @return TRUE if success, otherwise FALSE. */static int do_delete(apr_dbm_t *db){    apr_status_t rv;    apr_datum_t key;    key.dptr = MY_KEY1;    key.dsize = sizeof(MY_KEY1);    if ((rv = apr_dbm_delete(db, key)) != APR_SUCCESS) {        return FALSE;    }    printf("deleted\n");    return TRUE;}