LINUX使用C调用LMDB的方法

make && sudo make install

mkdir testdb

./mtest

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include <math.h>
#include <time.h>
#include <sys/time.h>
#include <sys/stat.h> 
#include "lmdb.h"
#define E(expr) CHECK((rc = (expr)) == MDB_SUCCESS, #expr)
#define RES(err, expr) ((rc = expr) == (err) || (CHECK(!rc, #expr), 0))
#define CHECK(test, msg) ((test) ? (void)0 : ((void)fprintf(stderr, \
  "%s:%d: %s: %s\n", __FILE__, __LINE__, msg, mdb_strerror(rc)), abort()))
#define TEST_DB_DIR  "./testdb"
int main(int argc,char * argv[])
{
  int i = 0, j = 0, rc;
  MDB_env *env;
  MDB_dbi dbi;
  MDB_val key, data;
  MDB_txn *txn;
  MDB_stat mst;
  MDB_cursor *cursor, *cur2;
  MDB_cursor_op op;
  int count;
  int *values;
  char sval[32] = "";
mkdir(TEST_DB_DIR, S_IRWXU | S_IRWXG | S_IRWXO);
  srand(time(NULL));
     count = (rand()%384) + 64;
     values = (int *)malloc(count*sizeof(int));
     for(i = 0;i<count;i++) {
    values[i] = rand()%1024;
     }
  E(mdb_env_create(&env));
  E(mdb_env_set_maxreaders(env, 1));
  E(mdb_env_set_mapsize(env, 10485760));
  E(mdb_env_open(env, TEST_DB_DIR, MDB_FIXEDMAP /*|MDB_NOSYNC*/, 0664));
  E(mdb_txn_begin(env, NULL, 0, &txn));
  E(mdb_dbi_open(txn, NULL, 0, &dbi));
  key.mv_size = sizeof(int);
  key.mv_data = sval;
  printf("Adding %d values\n", count);
     for (i=0;i<count;i++) {  
    sprintf(sval, "%03x %d foo bar", values[i], values[i]);
    /* Set <data> in each iteration, since MDB_NOOVERWRITE may modify it */
    data.mv_size = sizeof(sval);
    data.mv_data = sval;
    if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE))) {
    j++;
    data.mv_size = sizeof(sval);
    data.mv_data = sval;
    }
     }
  if (j) printf("%d duplicates skipped\n", j);
  E(mdb_txn_commit(txn));
  E(mdb_env_stat(env, &mst));
  E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
  E(mdb_cursor_open(txn, dbi, &cursor));
  while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
    printf("key: %p %.*s, data: %p %.*s\n",
    key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
    data.mv_data, (int) data.mv_size, (char *) data.mv_data);
  }
  CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
  mdb_cursor_close(cursor);
  mdb_txn_abort(txn);
  j=0;
  key.mv_data = sval;
     for (i= count - 1; i > -1; i-= (rand()%5)) {
    j++;
    txn=NULL;
    E(mdb_txn_begin(env, NULL, 0, &txn));
    sprintf(sval, "%03x ", values[i]);
    if (RES(MDB_NOTFOUND, mdb_del(txn, dbi, &key, NULL))) {
    j--;
    mdb_txn_abort(txn);
    } else {
    E(mdb_txn_commit(txn));
    }
     }
     free(values);
  printf("Deleted %d values\n", j);
  E(mdb_env_stat(env, &mst));
  E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
  E(mdb_cursor_open(txn, dbi, &cursor));
  printf("Cursor next\n");
  while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
    printf("key: %.*s, data: %.*s\n",
    (int) key.mv_size,  (char *) key.mv_data,
    (int) data.mv_size, (char *) data.mv_data);
  }
  CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
  printf("Cursor last\n");
  E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
  printf("key: %.*s, data: %.*s\n",
    (int) key.mv_size,  (char *) key.mv_data,
    (int) data.mv_size, (char *) data.mv_data);
  printf("Cursor prev\n");
  while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_PREV)) == 0) {
    printf("key: %.*s, data: %.*s\n",
    (int) key.mv_size,  (char *) key.mv_data,
    (int) data.mv_size, (char *) data.mv_data);
  }
  CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
  printf("Cursor last/prev\n");
  E(mdb_cursor_get(cursor, &key, &data, MDB_LAST));
    printf("key: %.*s, data: %.*s\n",
    (int) key.mv_size,  (char *) key.mv_data,
    (int) data.mv_size, (char *) data.mv_data);
  E(mdb_cursor_get(cursor, &key, &data, MDB_PREV));
    printf("key: %.*s, data: %.*s\n",
    (int) key.mv_size,  (char *) key.mv_data,
    (int) data.mv_size, (char *) data.mv_data);
  mdb_cursor_close(cursor);
  mdb_txn_abort(txn);
  printf("Deleting with cursor\n");
  E(mdb_txn_begin(env, NULL, 0, &txn));
  E(mdb_cursor_open(txn, dbi, &cur2));
  for (i=0; i<50; i++) {
    if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, MDB_NEXT)))
    break;
    printf("key: %p %.*s, data: %p %.*s\n",
    key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
    data.mv_data, (int) data.mv_size, (char *) data.mv_data);
    E(mdb_del(txn, dbi, &key, NULL));
  }
  printf("Restarting cursor in txn\n");
  for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) {
    if (RES(MDB_NOTFOUND, mdb_cursor_get(cur2, &key, &data, op)))
    break;
    printf("key: %p %.*s, data: %p %.*s\n",
    key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
    data.mv_data, (int) data.mv_size, (char *) data.mv_data);
  }
  mdb_cursor_close(cur2);
  E(mdb_txn_commit(txn));
  printf("Restarting cursor outside txn\n");
  E(mdb_txn_begin(env, NULL, 0, &txn));
  E(mdb_cursor_open(txn, dbi, &cursor));
  for (op=MDB_FIRST, i=0; i<=32; op=MDB_NEXT, i++) {
    if (RES(MDB_NOTFOUND, mdb_cursor_get(cursor, &key, &data, op)))
    break;
    printf("key: %p %.*s, data: %p %.*s\n",
    key.mv_data,  (int) key.mv_size,  (char *) key.mv_data,
    data.mv_data, (int) data.mv_size, (char *) data.mv_data);
  }
  mdb_cursor_close(cursor);
  mdb_txn_abort(txn);
  mdb_dbi_close(env, dbi);
  mdb_env_close(env);
  return 0;
}