dbobj.c

#include <stdio.h>
#include <string.h>
#include <db.h>

#define F_NUM(name) \
    long name
#define F_TEXT(name,n) \
    struct { int len; char data[n]; } name

#define REC(name) struct Rec_##name

#define D_REC(name, ...) \
    REC(name) {\
        __VA_ARGS__ \
    }

#define F_REC(name, ...) \
    D_REC(, __VA_ARGS__) name

D_REC(rec,
    F_NUM(id);
    F_TEXT(label, 32);
    F_REC(user,
        F_NUM(foo);
    );
);

int main(int argc, char *argv[])
{
    REC(rec) rec = {
        .id = 1,
        .label = {5, "label"},
        .user = {
            .foo = 3
        }
    };

    db_create(&db, NULL, 0);
    db->open(db, NULL, NULL, NULL, DB_BTREE, DB_CREATE, 0664);

    memset(&key, 0, sizeof key);
    key.data = &rec;
    key.size = sizeof rec;

    memset(&value, 0, sizeof value);
    value.data = "test value";
    value.size = 11;

    db->put(db, NULL, &key, &value, 0);

    memset(&value, 0, sizeof value);
    db->get(db, NULL, &key, &value, 0);
    printf("value: '%s'\n", (char*)value.data);

    db->close(db, 0);
    return 0;
}