Article View: comp.sys.amiga.tech
Article #11855Re: ARRGGGHHHHHHHHHHHH!!!! BCPL!!!!!!
From: David Donley
Date: Thu, 16 Mar 1989 02:00
Date: Thu, 16 Mar 1989 02:00
51 lines
2629 bytes
2629 bytes
daveh@cbmvax.UUCP (Dave Haynie) writes:
>in article <13291@gryphon.COM>, ddave@pnet02.cts.com (David Donley) says:
>
>> HELP! I am trying to write a mountlist writing program. Could somebody
>> please tell me
>
>> 1. How can you tell if a BSTR or BPTR is NULL?
>
>Well, start with the BPTR. Based on the definition:
>
> BPTR = CPTR >> 2;
>
>One would expect a BPTR NULL to be 0>>2, which magically turns out to be
>the same as the CPTR NULL. Imagine that.
>
>A BCPL string (once de-referenced, of course) is empty is the first byte
>is 0. You may also note that again, in this one case, that's the same
>way you tell if a C string is empty. Of course, before de-referencing a
>BCPL string pointer, you'll have to check that it's non-NULL, and probably
>shift it's pointer into a CPTR, as most BCPL strings are pointed to by
>BPTRs.
>
>> 2. What has changed in the FileSysStartupMsg, DeviceNode, and fssm_Environ
>> since 1.2?
>
>The only thing I know of is that the environment is longer. The first longword
>of the environment tells you it's length. Under 1.2, DE_MEMBUFTYPE is the
>last word of the environment. Under 1.3, you can also have the following
>environment vector members (in order):
>
> ULONG DE_MAXTRANSFER The maximum number of bytes to transfer
> at a time.
> ULONG DE_MASK Address mask used to block out certain
> areas of memory.
> LONG DE_BOOTPRI Autoboot priority.
> ULONG DE_DOSTYPE Indicates the file system, SFS = 'DOS\0',
> FFS = 'DOS\1'
>
>> ddave@pnet02.CTS.COM ddave@pnet.gryphon.COM killer!gryphon!pnet02!ddave
>--
>Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests"
> {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy
> Amiga -- It's not just a job, it's an obsession
Thanks for the help, I just had some probabems with dn_Handler asd several
other things (like dn_GlobVec) being set to 0xFFFFFFFF when they weren't being
used. Is this true, or am I realy screwed up here?
Call my BBS at (213) 372-4494
Disclaimer: If it doesn't work, you did something wrong.
ddave@pnet02.CTS.COM ddave@pnet.gryphon.COM killer!gryphon!pnet02!ddave
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!elroy!gryphon!pnet02!ddave From: ddave@pnet02.cts.com (David Donley) Newsgroups: comp.sys.amiga.tech Subject: Re: ARRGGGHHHHHHHHHHHH!!!! BCPL!!!!!! Message-ID: <13361@gryphon.COM> Date: 16 Mar 89 02:00:17 GMT Sender: root@gryphon.COM Organization: People-Net [pnet02], Redondo Beach, CA. Lines: 51