lmdb_rdonly2.c

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "lmdb.h"

#define DBDIR       "./testdb"

static MDB_env *env;

static void *thread_func(void *pArg)
{
    int code = (int)pArg;       //warningが出るが、気にしない

    int rc;
    MDB_txn *txn;
    unsigned long flags = 0;
    switch (code) {
    case 1:
        flags = 0;
        break;
    case 2:
        sleep(1);
        flags = MDB_RDONLY;
        break;
    }

    fprintf(stderr, "txn begin: code=%d\n", code);
    rc = mdb_txn_begin(env, NULL, flags, &txn);
    if (rc) {
        fprintf(stderr, "fail: mdb_txn_begin(%d:%s)\n", code, mdb_strerror(rc));
        goto LABEL_EXIT2;
    }

    printf("sleeping(%d)...\n", code);
    sleep(10);
    printf("wake up(%d)\n", code);

    mdb_txn_abort(txn);

LABEL_EXIT2:
    return NULL;
}

int main(void)
{
    int rc;

    mkdir(DBDIR, 0755);

    rc = mdb_env_create(&env);
    if (rc) {
        fprintf(stderr, "fail: mdb_env_create(%s)\n", mdb_strerror(rc));
    }
    rc = mdb_env_open(env, DBDIR, MDB_FIXEDMAP, 0664);
    if (rc) {
        fprintf(stderr, "fail: mdb_env_open(%s)\n", mdb_strerror(rc));
        goto LABEL_EXIT1;
    }

    pthread_t th1;
    pthread_create(&th1, NULL, &thread_func, (void *)1);

    pthread_t th2;
    pthread_create(&th2, NULL, &thread_func, (void *)2);

    pthread_join(th1, NULL);
    pthread_join(th2, NULL);

LABEL_EXIT1:
    mdb_env_close(env);

    return 0;
}