Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!sdd.hp.com!wuarchive!mit-eddie!bloom-beacon!eru!hagbard!sunic!news.funet.fi!funic!santra!santra!robin
From: robin@niksula.hut.fi (Jarto 'Robin' Tarpio)
Newsgroups: comp.sys.amiga
Subject: Re: AmigaDOS from BASIC....
Message-ID: <ROBIN.90Dec16122002@robin.hut.fi>
Date: 16 Dec 90 11:20:02 GMT
References: <730026@hpmwngf.HP.COM> <643@cbmger.UUCP>
Sender: news@santra.uucp (Cnews - USENET news system)
Organization: Helsinki University of Technology, Finland
Lines: 69
In-Reply-To: peterk@cbmger.UUCP's message of 14 Dec 90 16:53:35 GMT

In article <643@cbmger.UUCP> peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:

   Now, the interesting part of the program, where a List command is
   executed, is normally outcommented, because you have to assure one
   additional thing: To do things like this, you HAVE to invoke
   AmigaBASIC from Shell or CLI, NOT Workbench! To call DOS, AmigaBASIC
   needs this CLI background, else you get a real Guru.

	Not exactly. If you open a file for output and give it's FileHandle
	to the oputput in dos.library's Execute(), you can call DOS no
	matter where you started your program from. And open the output-
	file with dos.library's Open to get the FileHandle. (dos: XOpen)

	It's not a very good idea to read a dir by examining the output
	of list or dir. But it's the easiest way :-)

	For sporty ones: Here's how you should do it in principal:

	- Allocate 260 bytes for FileInfoBlock	(exec:AllocMem)
	- Lock the dir				(dos:Lock)
	- Examine the dir			(dos:Examine)
	- Test if it was a dir and not a file
	  PEEKL(FileInfoBlock+4) positive

	- Let's loop !
	- Take the next file/dir with ExNext	(dos:ExNext)
	- If it returned 0, it was the last one
	- The name starts at FileInfoBlock+8
	  and is null-terminated.
	- If PEEKL(FileInfoBlock+4) positive,
	  it was a dir.
	- Back to the beg of loop !

	- Clean up:
	- UnLock the dir			(dos:UnLock)
	- Free the FileInfoBlock		(exec:FreeMem)


	To start with:

	LIBRARY "exec.library"
	LIBRARY "dos.library"

	DECLARE FUNCTION AllocMem&() LIBRARY
	DECLARE FUNCTION Lock&() LIBRARY
	DECLARE FUNCTION Examine&() LIBRARY
	DECLARE FUNCTION ExNext&() LIBRARY

	For example:

	The allocation:	FIB&=AllocMem&(260,65537)
	The lock:	DirLock&=Lock&(SADD(YourDir$),1005)
	The examine:	Success&=Examine&(DirLock&,FIB&)

	These are not at all detailed instructions, but it's always the
	hardest thing to find out the idea. Go step by step and examine,
	what you get. And be prepared to gurus ! If you do mistakes
	allocating the FIB and give FIB&=0 to Examine, the ExecBase doesn't
	like it at all :-)

   -- 
   Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
   Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

/robin

--
Jarto Tarpio	StarSoft Ky, Finland	ADSPE: Commercial ECO101
Helsinki University of Technology       EMAIL: robin@niksula.hut.fi