Question: I'm using NHibernate to map my objects to the DB. One of these object is called "Attachment". its ID is generated using the "newsequentialid" in MS SQL server 2008 (as the Default Value or Binding) to create the Guid for the id column.

Now what i want is that when a new Attachment is inserted then NHibernate will allow the SQL Server to create the Guid using the newsequentialid. Thing is that the i keep getting an exception "null identifier" when trying to save a new Attachment where the id is not set (Guid.Empty)

here is my HBM file:

```
<class name="DataObjects.Services.NHAttachment, DataObjects, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" mutable="false" table="Attachments">
    <id name="Id" column="Guid" type="Guid" >
      <generator class="native"  />
    </id>.....

```

As you can see the ID is set with a generator class as native.

Thanks for all the help in advance!! :)

Answer: 
Typically, you define `-l` options to the linker using LDLIBS, and `-L` flags using LDFLAGS. Edit the Makefile and add the appropriate options.

```
CPPFLAGS += -I/usr/local/ssl/include 
LDFLAGS += -L/usr/local/ssl/lib 
LDLIBS += -lcrypto -lm

```
These are compiler errors, you haven't got to the linking stage yet.

I would guess that, when compiling tgl\_frbsenddata.ec, the compiler doesn't know what a DES\_cblock is or a DES\_key\_schedule. At the point where the compiler hits the lines with the errors in, I suspect des.h has not yet been included whatever you may believe about whether you have or not. 

Your compiler probably includes an option to do preprocessing only (in gcc and clang, it is `-E`). I suggest you run it with that option on your source file to see if the typedefs appear.