path: root/doc/ports/vmsbugs.doc

From stsci Thu Jan 17 08:30:15 1985
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	id AA10600; Thu, 17 Jan 85 08:30:03 mst
Date: Thu, 17 Jan 85 08:30:03 mst
From: stsci (Space Telescope )
Message-Id: <8501171530.AA10600@lyra.noao.UUCP>
To: tody
Status: R

Doug,

	Here is a list of bugs, changes, suggestions, etc. compiled during
the port of IRAF to VMS.

	Some of the bugs have the bug fixes listed here; others were too
elusive and/or time-consuming to try to figure out at this time.  When you 
get the latest, greatest VMS version of IRAF, what changes we made will 
certainly be there;  we'll probably send along RCS files as well so you could
easily update some of your files.  However, most of the changes are
just a few lines here and there.

	We await any comments or any bug fixes you have there...

				Jay and Fred

P.S.
	We were discussing using mapped sections such as sdas
uses for static files. There is one major difference in the way that
iraf and sdas handle static (image) files. In the sdas routine
a pointer is passed back to where the image resides in memory. This
is due to the way the mapped sections work in VMS. In Iraf the zroutine
is given a pointer to where the data is to reside, so we have to do
a memory copy for each image reference, and may not be more efficient
than just writing to or reading from disk. Can you see any easy
way around this problem, or maybe an additional flag to zopnsf which
indicates that a pointer is to be passed back from zardsf or zawrsf
for the data rather than a passing in a pointer to where the data is to
be read to or written from?    (fred)


----------------------------------------------------------------------------


			------------------------
			NOTES file for IRAF (VMS)
			------------------------


Contents:
		1.	Bugs 

		2.	Portability Considerations

		3.	Source file name changes


-------------------------------------------------------------------------------


1.	Bugs 

	/pkg/cl/bkg.c
		In rbkgfile(), following fix:
			... fgets (set, fp) ...    	TO
			... fgets (set, SZ_LINE, fp) ...

	/sys/libc/qsort.c	--	qcmp()    -->  (*qcmp)()
	/sys/libc/cfilbuf.c	--	filbuf()  -->  (*filbuf)()

	/sys/vops/advz.x	--	'$t' missing for generic function
	/sys/vops/advz*.x	--	procedure advz[idx...]

						(extra files ?)
	/sys/vops/ak/aif*.x	--	aiftrrr.x
	/sys/vops/ak/aff*.x	--	afftrxx.x,  afftxrr.x,  afftxxx.x
	/sys/vops/ak/acjgx.x	--	acjgxx.x

	/sys/fio/fdebug.x	--	"int and()" statement missing
	/sys/fio/fputtx.x	--	"int and()" statement missing
	/sys/fio/fgetfd.x	--	"int or()"  statement missing

	/pkg/cl/pfiles.c	--	pfcopyback()
		'pt' was going NULL before 'pf' in a for loop check;
		was changed to check for 'pt' being NULL instead of 'pf'

	/pkg/cl/builtin.c, binop.c, bkg.c, history.c, lexicon.c,
		debug.c, errs.c, exec.c, pfiles.c

		problem getting to next task by doing  'tp++'; due to VMS
		alignment of structures.  Fixed with a macro definition in
		/pkg/cl/task.h  for "next_task()", namely:

		#define  next_task(tp)  \
			((struct task *)((unsigned)tp + (TASKSIZ * BPI)))
		#define  prevtask  next_task(currentask)


	/pkg/help/lroff/output.x --	references constant MAX_INT
					"include <mach.h>" statement missing

	/pkg/lists/tokens.x	--	last_nscan() --> last_nscan

	SPP/RPP compiler bug	--

			define  and  jiand	(e.g. in <iraf.h>)

			if (x == FIVE  &&  y == SIX) ...	(SPP)
			if (x == FIVE  &   y == SIX) ...	(RPP)
			if (x .eq. 5  .jiand.  y .eq. 6) ...	(FORTRAN)

		only occurs when a macro is replaced before the '&&', 
		in this case FIVE.

	/sys/fio/vfnmap.x
		vfnunmap() -- when an OS extension was (un)mapped to a null
			      IRAF extension, the character count returned
			      was not right:
				(e.g.)	doc.dir --> doc   but nchars = 7
                              This caused problems later on in the directory
	                      task of the system package.
			The fix:
					...   {
				vfn[extn_offset-1] = EOS
				op = extn_offset - 1		<-- was missing
			        }	...

	/sys/fio/vfntrans.x
		filename mapping for directories sometimes doesn't work;
			sys$  -->  drb4:[irafx.sys]sys   instead of
				   drb4:[irafx.sys]
		made a quick fix in zopdir() and zfchdr() to deal with this
		for now; can't seem to locate the exact problem in vfntrans.x

	/sys/fio/vfnmap.x
		When deleting a file and the parameter subfiles=yes, and
		no mapping file is currently in directory, a null mapping
		file is (sometimes) created.  Then doing a system.directory 
		fails when trying to read this null mapping file.

		E.g.  cl> delete aaabbb.ccc
			subfiles=yes (default .par file)

			delete() is called with 'aaabbb.ccc' and then
				'aaabbb.ccc.zsf', which is degenerate;
				therefore, if a mapping file doesn't 
				exist, it is created.

		Haven't fixed this yet; not sure about the best way to go.
		Some simple suggestions:

		  --	Could somehow figure out whether the file is being
			added or deleted (i.e. was vfnmap() called from 
			vfnadd() or vfndel()?).  

		  --	Or, whenever a mapping file is created, it has the 
			appropriate header info in it rather than being null?  

		  --	Or, some special case of reading null mapping files?


	/sys/etc/environ.x
		env_hash()  
			return (sum**2 / CONSTANT)

		causes integer overflow on VMS; changed to:  (for now)
			return ( int( float(sum) / CONSTANT * float(sum) ) )

	arithmetic overflows:
		/sys/etc/urand.x  and  others...

		These seem to occur in a few places, sometimes purposely.
		An easy VMS fix is to use "FORTRAN/NOCHECK file", but it's
		a pain to have to remember which files need this special
		treatment.

	/sys/fio/
		Seems to be a bug in the file i/o related to writing 
		asynchronously to binary files.  In VMS, this is REALLY
		asynchronous, and it caused problems when trying to write
		the help database;  making VMS do it synchronously (like
		UNIX) fixed the problem, for now anyway.

		It may be that a single buffer is being played with between
		the write and the wait;  at least that's what it looks like
		in some of the binary files that were written -- there were
		missing blocks and misaligned data, which were there when
		displayed on the terminal.  

		I don't think it's a problem with RMS, since double buffering
		was used to test the binary file driver, with success.


	/pkg/system/directory.x
		- call strcat ("$", Memc[template])    -->
 		  call strcat ("$", Memc[template], SZ_FNAME)

		- should sort and output the file name list ONLY 
				if (nfiles > 0)
		  otherwise, an "adjustable array error" occurs in qsort()
		  (i.e. an array with dimension of 0 is passed to qsort,
		        causing VMS to complain)


-------------------------------------------------------------------------------


2.	Portability Considerations


	(life would be easier if most source files and include files did
	 not need to be mapped ... especially C source files)
	
			--	no underscores
			--	only alphanumeric
			--	case insensitive (i.e. lower case)
			--	(9 chars).(3 chars)

	(Notes: Some source file names and references to include files
		had to be changed to create the filename mapping in the 
		first place, see list below.  

		This is not so crucial now, since XC and XPP have been
		written/modified to handle filename mapping.  But, it
		still does cause problems when making bug fixes to source
		files with degenerate names and trying to keep track of
		them with RCS.  Of course, 99% of the mapping problems will
		disappear with VMS V4.0.)

	also, directories should be case insensitive:
		/sys/vops/AK	-->  ak
		/sys/vops/LZ	-->  lz


	sys/libc/cfilbuf.c	--	filbuf  -->  vfilbuf (VMS)
					since 'FILBUF' gets translated to
					'filbuf' on VMS, not 'filbuf_', 
					which causes a conflict:
						FILBUF and (*filbuf)()


	SPP coding conventions that cause problems for VMS FORTRAN compiler:

	a)  multiple declarations, e.g.

			int  ip
			   ...
			int  ip, this, that

	    files:	/sys/fmtio/ctoi.x
			/sys/fmtio/sscan.x
			/sys/fmtio/chdeposit.x
			/pkg/system/sort.x

	b)  'real' function, e.g.

		real (dval, 0)  -->  real (dval, 0.0)
			/sys/fmtio/gctod.x

	c)  array declarations in procedures, e.g.

		procedure proc1 (array, count)
		type  array (count)
		int   count		# should be BEFORE array declaration
					# (tries to use 'count' as a REAL)
			/sys/fmtio/patmatch.x
			/pkg/utilities/t_translit.x
						makeset(), filset()


	and(), or(), not()  -->  andi(), ori(), noti() ???
		lots of references in /sys/fio/ to these procedures 
		(added them for VMS, using andi(),...)
	xor()  referenced in  /sys/vops/...axorki.x
		(added xor() for VMS, using xori())

	FIO
		file mode "APPEND" -- create the file if non-existent??
		UNIX (and now VMS) do this automatically, but system
		reference document isn't clear about this.  Without this
		feature,  /pkg/system/bugmail.cl and revisions.cl  don't work.

	I/O drivers
		ZMAIN passes the EPA of the read driver to IRAF_MAIN() ...

		This is OK in UNIX (and VMS, for now), but may have cases 
		where I/O is to different devices and the drivers are NOT 
		compatible.  (I don't know enough of the internals of 
		other operating systems to say for sure that this is a
		problem, but it seems like it could be.)

		Eg.   STDIN from a file and STDOUT to terminal

		If the file and terminal drivers are incompatible, then
		things won't work.  We may eventually have some problems
		in this area with VMS, especially if we start to support
		some network I/O access.  Eventually, we may store the
		actual read/write function in the channel structure and 
		check it whenever a read/write function is called; that is,
		override the higher level IRAF I/O at the kernel level.

	zardlp() function referenced in  /sys/etc/lpopen.x ??
		(added dummy function for VMS)


	modf()  function used in  /pkg/cl/unop.c
		was missing from /sys/libc/
		(added  modf.mar  to /sys/os/ for VMS)


-------------------------------------------------------------------------------


3.	Source file name changes


	/pkg/softools/boot/spp/xpp/xpp_main.c  -->  xppmain.c

	Necessary for file name mapping:

		/sys/memio/ty_size.dat  -->  tysize.dat

		/sys/memio/coerce.x, salloc.x, sizeof.x
			include "ty_size.dat"  -->  include "tysize.dat"


-------------------------------------------------------------------------------