lmdb-safe/examples/basic.cc

#include "../lmdb-safe.hh"

#include <iostream>

using namespace std;
using namespace LMDBSafe;

void checkLMDB(MDBEnv *env, MDBDbi dbi)
{
    auto rotxn = env->getROTransaction();
    MDBOutVal data;
    if (!rotxn->get(dbi, "lmdb", data)) {
        cout << "Outside RW transaction, found that lmdb = " << data.get<string_view>() << endl;
    } else
        cout << "Outside RW transaction, found nothing" << endl;
}

int main()
{
    auto env = getMDBEnv("./basic.lmdb", MDB_NOSUBDIR, 0600);
    auto dbi = env->openDB("example", MDB_CREATE);

    auto txn = env->getRWTransaction();
    mdb_drop(*txn, dbi, 0);
    txn->put(dbi, "lmdb", "great");

    MDBOutVal data;
    if (!txn->get(dbi, "lmdb", data)) {
        cout << "Within RW transaction, found that lmdb = " << data.get<string_view>() << endl;
    } else
        cout << "Found nothing" << endl;

    std::thread elsewhere(checkLMDB, env.get(), dbi);
    elsewhere.join();

    txn->commit();

    cout << "Committed data" << endl;

    checkLMDB(env.get(), dbi);
    txn = env->getRWTransaction();
    mdb_drop(*txn, dbi, 0);
    txn->commit();
}