newdlist = MakeDosEntry(name, type)
D0 D1 D2

struct DosList *MakeDosEntry(STRPTR, LONG)

Three code examples are provided which show how to create a DLT_DEVICE
type DosList entry such as may be used for the "PRT:" device using
the "L:Port-Handler", for a simple device which expects a string
in the dol_Startup member and for a "RAD:" file system which makes
use of the ramdrive.device storage device.

The fourth example shows how you would figure out if the
DosList->dol_misc.dol_handler.dol_Startup member refers to a
BCPL string, a BCPL pointer to a 'struct FileSysStartupMsg' or
none of these two.

1. "PRT:" device and "L:Port-Handler"

This is an example of a handler which uses the dos.library V34
BCPL legacy interface which requires that the dol_GlobVec
member is filled in. Do not use this, it is just to show how
it would be done. Note that dol_Startup is set to the number 2,
which would tell Port-Handler to open "printer.device"; the value
0 would have it open "serial.device" and the value 1 would have
led to "parallel.device" being opened.

---------------------------------------------------------------------
#include <dos/dosextens.h>
#include <string.h>

extern struct DosLibrary * DOSBase;

const TEXT handler_name[] = "L:Port-Handler";
UBYTE * bcpl_handler_name = NULL;
struct DosList * dol = NULL;
LONG success = FALSE;
int len;

/* Allocate memory for a NUL-terminated BCPL string.
len = strlen(handler_name);
if (len <= 254)
if (bcpl_handler_name != NULL)
{
}

if (success == FALSE)
{
}
---------------------------------------------------------------------

2. Simple "EXAMPLE:" device with startup string

This is a very simple example which shows how you set up and
install a NUL-terminated BCPL string in the dol_Startup member,
if it is needed. This is not a complete example of how a
handler would be set up.

---------------------------------------------------------------------
#include <dos/dosextens.h>
#include <string.h>

const TEXT startup[] = "quiet";
UBYTE * bcpl_startup = NULL;
struct DosList * dol = NULL;
LONG success = FALSE;
int len;

/* Allocate memory for a NUL-terminated BCPL string.
len = strlen(startup);
if (len <= 254)
if (bcpl_startup != NULL)
{
}

if (success == FALSE)
{
}
---------------------------------------------------------------------

3. "RAD:" file system which makes use of the ramdrive.device

This example shows in detail how you might mount a file system
which uses a mass storage device driver after dos.library has
already booted the system. This is different from how you would
set up a partition as part of an Autoboot hard disk controller.
In that case, you would use the expansion.library functions
MakeDosNode() and AddBootNode(). MakeDosNode() performs all the
steps shown in the following example, save for the default file
system seglist access, because dos.library is not operational at
the time an Autoboot hard disk controller will set up the
partition information.

Please note that this setup procedure which fills in dol_GlobVec=0
and then initializes dol_SegList from the DOSBase default file system
segment list has a very limited use. It basically works only for the
default file system. For real use, you would adopt an entry found in
the FileSystem.resource list which matches the DOS Type you expect.
This is the same approach which an Autoboot hard disk controller
makes use of.

Finally, how do you activate a file system which has been mounted?
Call DeviceProc(), which will look up the DosList entry for the
file system device and start the file system Process, if this has
not been done yet. In the example below, you would accomplish this
by calling DeviceProc("RAD:"), after having successfully added the
new DosList entry.

---------------------------------------------------------------------
#include <dos/dosextens.h>
#include <dos/filehandler.h>
#include <string.h>

extern struct DosLibrary * DOSBase;

const TEXT device_name[] = "ramdrive.device";
const LONG unit_number = 0;
const LONG opendevice_flags = 0;
UBYTE * bcpl_device_name = NULL;
struct DosEnvec * de;
struct FileSysStartupMsg * fssm;
struct DosList * dol;
LONG success = FALSE;
int len;

/* Allocate memory for a NUL-terminated BCPL string.
len = strlen(device_name);
if (len <= 254)
/* Allocate memory for the DOS environment vector, which is a
de = AllocVec((1+DE_DOSTYPE) * sizeof(LONG),
/* Allocate memory for the FileSysStartupMsg structure which
fssm = AllocVec(sizeof(*fssm), MEMF_ANY|MEMF_PUBLIC|MEMF_CLEAR);

if (bcpl_device_name != NULL && de != NULL && fssm != NULL)
{
}

if (success == FALSE)
{
}
---------------------------------------------------------------------

4. How to tell what DosList->dol_misc.dol_handler.dol_Startup means
A handler or file system may need to know how and by which means it
should do its job. For example, the Amiga ROM default file system
can be used with a variety of mass storage device drivers which
implement the same command set: the file system just needs to know
which device driver, device unit and partition configuration to use.
The Port-Handler needs to know which specific device driver should
be accessed when you open the SER:, PAR: or PRT: AmigaDOS devices.
This kind of information is provided through the DosList
dol_misc.dol_handler.dol_Startup member:

- A "simple" handler such as the original Workbench 1.1 Port-Handler
- A handler may also expect to find a pointer to a BCPL string in
- A file system which makes use of a mass storage device driver will
Regardless of what information is provided for the file system or
handler, it will need to be validated before it can be put to use.
This is the main reason why you should be able to identify the
kind and format of information expected. This knowledge is useful
for debugging and diagnostics, too.

Identifying an integer value stored in dol_Startup is comparatively
easy, but a BCPL pointer to a BCPL string or to a FileSysStartupMsg
is harder to identify reliably as what it is. The following example
code attempts to break down the value into three categories, with
"unknown" (dol_startup_unknown) as the fourth option if no other
category makes sense. Please note that if dol_startup_bstr is returned
you should inspect what appears to be a BCPL string and validate
its contents. For example, check if the string length is > 0 and
if all the characters of the string make sense.

---------------------------------------------------------------------
#include <dos/dosextens.h>
#include <dos/filehandler.h>

/* This is a simple test to check if a BPTR may point to a valid
#define IS_VALID_BPTR_ADDRESS(ptr) (((ptr) & 0xC0000000) == 0)

/* Which kind of information may be stored in the DosList
enum dol_startup_t
{
};

enum dol_startup_t
get_dol_startup_type(const struct DosList * dol)
{
}
---------------------------------------------------------------------