t.c

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

#include "sqlite3.h"

#define CHECK                                                                   \
    do                                                                          \
    {                                                                           \
        if (res != SQLITE_OK)                                                   \
        {                                                                       \
            fprintf(stderr, "Failed at line %d with code %d\n", __LINE__, res); \
            exit(1);                                                            \
        }                                                                       \
    } while (0)

int main(int argc, char **argv)
{
    int res;
    sqlite3 *db = NULL;
    unsigned char *serialized = NULL;
    sqlite3_int64 serial_size = 0;

    void *datacopy = NULL;

    /* in memory db with default flags */
    res = sqlite3_open_v2("", &db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL);
    CHECK;

    /* create a table so the database is not empty */
    res = sqlite3_exec(db, "create table foo(x)", NULL, NULL, NULL);
    CHECK;

    /* serialize */
    serialized = sqlite3_serialize(db, "main", &serial_size, 0);
    /* verify we got data back */
    res = (serial_size != 0) ? SQLITE_OK : SQLITE_ERROR;
    CHECK;

    /* copy the data */
    datacopy = sqlite3_malloc64(serial_size);
    memcpy(datacopy, serialized, serial_size);

    /* free serialized (caller is responsible for freeing the returned value to avoid a memory leak) */
    sqlite3_free(serialized);

    /* now load data into temp */
    res = sqlite3_deserialize(db, "temp", datacopy, serial_size, serial_size, SQLITE_DESERIALIZE_RESIZEABLE | SQLITE_DESERIALIZE_FREEONCLOSE);
    CHECK;

    sqlite3_close(db);
    return 0;
}