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Conference bulova::decw_jan-89_to_nov-90

Title:	DECWINDOWS 26-JAN-89 to 29-NOV-90
Notice:	See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit
Moderator:	STAR::VATNE

Created:	Mon Oct 30 1989
Last Modified:	Mon Dec 31 1990
Last Successful Update:	Fri Jun 06 1997
Number of topics:	3726
Total number of notes:	19516

741.0. "On porting X->DECW" by PCINT::MERRILL (Brad Merrill DECtp SWE) Mon May 08 1989 19:14

       This is an attempt to chronicle the steps of converting an X-windows
application to DECwindows.  Xconq was a particularly well written program
with system specific calls surrounded by conditional compilation.  Additionally
all the X routine calls were contained in one module.  I don't know how much
this experience may help anyone else, doing a similar port.

       The entire port was done over a 2 week period, of completely off hours
work.  Suffice to say, a full time port could have been done in less time.

========================================================================

COPY DECWRL::"/pub/X11.contrib/Xconq5.tar.Z" XCONQ5.Z

LZDCMP -B xconq5.z xconq5.tar

TARREAD XZ xconq5.tar

Convert MAKEFILE. to XCONQ.MMS

modify CONFIG.H
	Used "xconq" & "xconq-standard" for font names,
	used "-DEC-Terminal..." for textfont.

modify X11.C
	Replaced "#include <X11/" with "#include <DECW$INCLUDE/".
	Found all "#ifdef UNIX", and provided compatible code with
	"#ifdef VMS" around it.

	Changed "getenv("DISPLAY")" to "getenv("DECW$DISPLAY")".

Additional DECwindows specific changes were found:
    Modified the font size calculations for VMS.  It seems that the author
    was adding MAX_BOUNDS.ASCENT + MIN_BOUNDS.DESCENT.  The min_bounds
    number is negative, and actually ended up truncating the line height.
    Is this perculiar to DECwindows?

    Modified the open_font call to prefix undefined fontnames with "xconq-"
    on the next try.  Perhaps there should be some naming conventions for
    user defined fonts.

    Removed complaining when available color was not exactly default color.
    I don't know why this was here, and it was annoying.

    Added new select style SELECT3.  This is to add a compatible multiplexer
    that is similar to the SELECT call on UNIX.

modify .BDF files to use vms style naming
	Changed FONT name "/usr/..." to "xconq-*"

Compile fonts:
	FONT XCONQ.BDF/OUT=XCONQ.DECW$FONT
	FONT STANDARD.BDF/OUT=XCONQ-STANDARD.DECW$FONT
	COPY *.DECW$FONT SYS$COMMON:[SYSFONT.DECW.USER_75DPI]

Restart the DECwindows server
	@SYS$MANAGER:DECW$STARTUP "RESTART"

Define logical names
	$ DEF XCONQ$LIBRARY ==> directory containing predefined
				maps/scenarios/periods/fonts
compiling
	$ MMS/DESCRIPTION=XCONQ X11CONQ

create symbol
	$ XCONQ :== $disk:[dir]x11conq.exe

execution
	$ XCONQ

modified .B files
	Replaced ending "0x0000, }" with "0x0000}".  For some reason
	the read bitmap routines didn't like the former.

converted NROFF documentation to LaTex
	I don't use Document.

converted XCONQ.6 to XCONQ.HLP
	I have now tested the multi-player capabilities locally.

T.R	Title	User	Personal Name	Date	Lines
741.1	Don' change #includes	VINO::WITHROW	Robert Withrow	`Tue May 09 1989 14:03`	9
	> modify X11.C > Replaced "#include <X11/" with "#include <DECW$INCLUDE/". > Found all "#ifdef UNIX", and provided compatible code with > "#ifdef VMS" around it. Recommend not doing this as it just builds in another incompatability. Rather, $define x11 decw$include. Even if included in a #ifdef it is unnecessary noise.
741.2	It is not quite obvious...WHAT IS DECWINDOWS?!	32956::graham	Rude Movements.....	`Thu May 11 1989 20:07`	17
	Should this note have a title like.. "Porting UNIX/X11" code to DECwindows/VMS" or something similar? [The xconq will run under Ultrix without a single line change.] Based on the premise that DECwindows is supported under DOS, Ultrix and VMS. Flame: This kind of noting is very rampant in this conference! Flame off: Kris..
741.3	Can a novice port X -> VMS DECwindows?	TALLIS::INGRAHAM		`Fri Feb 23 1990 16:46`	22
	This is a novice question. I've only looked into this notesfile a little; hope I'm not boring you with yet-another-novice-question, or you're-in- the-wrong-notesfile, or something to that effect. I have a program, that was written to optionally use the X windowing system. And now, due to a VMS upgrade, I find myself with a workstation in front of me that is capable of running DECwindows, only a reboot away. DECwindows is based on X, right? So it might be possible to make this application work under DECwindows (he says, naively). So the question is: Can I make the application "play" DECwindows? How? How difficult is that likely to be, in general? I know zilch about X or DECwindows; I hack around a bit with programming; my real interest for now is kind of a "midnight hack" to see how the program runs and looks. (The program has bugs anyway.) Is this something a novice can just pick up and do, or should I not even try? Is one better off investing a few weeks/months and a course or some books to really learn DECwindows? I wasn't intending to become fluent in X or DECwindows programming, just get this one to work. Andy
741.4		CVG::PETTENGILL	mulp	`Fri Feb 23 1990 21:13`	12
	If it were simply a matter of the program being written for X rather than for Unix, then it would be a simple matter of compiling it and fixing minor bugs. Instead you will find that you need to both convert from Unix to VMS and make up for some unsupported X usage that is typical and an occasional incompatibility caused by the different baselevels of X used for each release. However, many people have hacked existing X programs in a very short time; sometimes as short as an hour. Sometimes they just compile and run. I suggest you check out the ELKTRA::DW_EXAMPLES conference; many of the things there are the result of similar efforts.
741.5		PSW::WINALSKI	Careful with that VAX, Eugene	`Fri Feb 23 1990 23:06`	10
	RE: .3 DECwindows is X Windows, so, as .4 said, aside from some possible minor version skew differences, the X calls themselves should require no modification at all. A lot of the X Windows freeware that's floating around was developed for Unix, and so the Unix-isms tend to be the real problem. I've ported several of these little programs to VMS DECwindows, and I never found the X calls to be a problem. What work I had to do involved Unix-isms. --PSW