SQLite Forum

Here is an example how to sqlite_mallo:

/** \brief Initialize the flag function extension
 *
 * \param db a pointer to the database
 * \param a point to a point for the error messages
 * \param a pointer to the SQLITE_API
 * \return SQLITE_OK
 *
 */
int sqlite3_extension_init(sqlite3* db, char **err, const sqlite3_api_routines *api)
{
    int rc = SQLITE_OK;
    int RegisterFlagFunctions(sqlite3 *);

	SQLITE_EXTENSION_INIT2(api)
    /**< Registers all flag functions */
    rc = RegisterFlagFunctions(db);
    if (rc != SQLITE_OK) {
        /* Error! */
        return rc;
    }

    /**< Need so memory from SQLite to store the flags */
    sptr = sqlite3_malloc(sizeof(Semaphore));
    ClearFlags();

    return rc;
}

By the way the extension is not in control of the memory block. SQLite is in control and therefor I am not deleting anything. You should check sptr not being NULL.