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RE: [xml] building libxml 2.4.6 under OpenVMS

Hello John,

for building libxml under OpenVMS you've proposed (among others) changes to
trionan.c:

138d145
< #define TRIO_DOUBLE_INDEX(x) (((unsigned char
*)&internalEndianMagic)[(x)])
140c147,148
< static CONST double internalEndianMagic = 1.4015997730788920e-309;
---

#define TRIO_DOUBLE_INDEX(x) (((unsigned char

*)&internalEndianMagic)[7-(x)])

static CONST double internalEndianMagic = 7.949928895127363e-275;


By a fluke this solves a problem that i was stucked in building libxml under
MPE,
that is compiler warnings (Floating constant exceeds its storage) and
crashes during runtime.
Do you know if it's save to apply these changes for other platforms?
Or does they only make sense in context with the other changes you've made?
You've indicated that the changes will be included in the distro. Are they
already?

Many thanx in advance & Ciao, Markus



-----Original Message-----
From: John A Fotheringham [mailto:jaf jafsoft com]
Sent: Wednesday, October 31, 2001 3:45 PM
To: xml gnome org
Subject: [xml] building libxml 2.4.6 under OpenVMS


I've managed to get libxml2 2.4.6 built under OpenVMS after a number
of changes and much help from Bjorn Reese and Daniel 
Veillard.  It seems
okay (programs built and run), though I haven't put the 
package through 

its paces yet.

Below are my notes on the issues I had to deal with.  Hopefully this
will be included as a readme file in future distros.  Attached is the
Unix doffs file for the code changes I had to make and the following
notes as readme file.  Anyone wanting a VMS doffs file can 
email me :-)

I also had to re-write the VMS build command file.  Daniel tells me
this will be included in 2.4.7 onwards.

Cheers, Jaf

------- 8< --------- cut here ----------- 8< -----------------------

Issues in porting libxml to VMS
===============================

Here's a summary of the issues I encountered when building LIBXML
under VMS.  There was some VMS support in the version I got, but
it was a little out of date with the result that some newer files
had problems.

I present this list "as is" to hopefully act as a guide to anyone
having problems in the future.

That's it.  Good luck!

John A Fotheringham (jaf jafsoft com)
October 2001


Installation kit
----------------

- File attributes.  Having downloaded essentially a Unix distribution,
   some of the file attributes weren't correct... especially those in
   the [.VMS] subdirectory.  In EDT you could see line feeds and
   carriage returns as <LF><CR> etc.  To correct this use the command

      $ set file <filespec> /attr=rfm=stm

   This sets the record format to be "stream".  Other variants may be
   used instead depending on how you got the files onto your system.
   Files will look okay in an EDT editor once the attributes are set.
   Without this the command file may not run correctly, since it may
   be interpreted as a single line.

- VMS-specific files are in a [.VMS] directory.  If you've found this
   file then you already know this :-)  This directory contains

       BUILD_LIBXML.COM       - a build command file, which I've
                                radically re-worked
       CONFIG.VMS             - a configuration file to 
replace config.h

- Don't execute BUILD_LIBXML.COM until you've done all the following

   - read these notes
   - copied CONFIG.VMS to CONFIG.H
   - reviewed the configuration section of BUILD_LIBXML.COM, and in
     particular updated the module lists in line with MAKEFILE
   - edited XMLVERSION.H so that WITH_TRIO is defined
   - identified the location of the include files, so that you can
     manually set the LIBXML logical if need be.
   - re-read these notes :-p

   instructions for all these steps are below.

- the file [.vms]config.vms should be used to replace config.h.
   This file contains a number of define statements that identify the
   software options required under VMS

- The include files are in a [.INCLUDE.LIBXML] subdirectory.  You
   need a logical "libxml" to point to this so that include statements
   of the form

      #include <libxml/parser.h>

   will work correctly.  The source files are mostly two levels
   above this directory, although there are some .h files there
   as well.

- The command file BUILD_LIBXML.COM will do the following

   - setup some logicals
   - set def to the source directory
   - compile modules and place them into a LIBXML.OLB library
   - compile and link a number of self-test programs
   - compile and link a number of utilities and test programs
   - set def back to the original directory (i.e. if it fails you
     might not be where you started :-)

   before running this command file review the configuration segment
   at the top.  In particular compare the lists of modules with those
   in the most recent version of the Unix MAKEFILE.  Instructions are
   contained in the command file itself.

   The command file will attempt to set two logicals

   - xml_srcdir.  The directory containing the source files
   - libxml.  The include file directory.

   It attempts this by looking for modules globals.c and globals.h
   in nearby directories.  If this logic fails, you'll need to
   manually define these logicals.


The TRIO package
----------------
- A sub-package TRIO is used to provide some functions not
   naturally available under VMS.  These include support for infinite
   and undefined numbers, and specialised print functions like
   "snprintf"

   I had to make several changes to trionan.c in discussion with
   the author (hopefully these are now included in the distro, so I
   won't list them here)

   To build this software we need to add

      /IEEE_MODE=UNDERFLOW_TO_ZERO/FLOAT=IEEE

   to the compile command for xpath.c and trio.c, and to any main
   program that uses this functionality.  BUILD_LIBXML.COM should
   do this for you.

- to build in trio support you need the define WITH_TRIO to be
   set.  This is done by editing xmlversion.h


Compiler and linker errors
--------------------------
- the DEC C compiler will produce a number of warnings when
   compiling the C code.  These include

     - Implicit function warnings.  These indicate functions whose
       type is not defined in a .h file.  This will probably only
       happen if your configuration is not correct (e.g. for
       "snprintf" if you haven't edited xmlversion.h to set WITH_TRIO

       These messages also occur for "read" and "write" when
       compiling trio.c

     - uninitialised variables.  Not usually a problem.  You can
       solve this by editing the code to initialise the variables
       affected

   and with respect to the trionan code

     - no main module for UNDERFLOW_TO_ZERO
     - float overflow when compiling trionan.c STANDALONE

   You can suppress these "expected" messages by using the compile
   command

     $ CC /WARN=DISABLE=(FLOATOVERFL,NOMAINUFLO)

   This can be achieved by specifying "NOWARN" as the first command
   parameter to BUILD_LIBXML as follows

     $ @BUILD_LIBXML NOWARN

- the Linker will report the following error

       %LINK-W-MULDEF, symbol DECC$STRERROR multiply defined
         in module DECC$SHR file SYS$COMMON:[SYSLIB]DECC$SHR.EXE;5

   This is complaining that DECC$STRERROR is multiply defined, which
   in turn is because this system symbol is getting added to
   LIBXML.OLB when strio.c is compiled.

   I'm not sure what the solution for this is, but this is a fairly
   benign error.


Changes made to the codebase
----------------------------
- I changed all dummy declarations in trio.c to be

     va_list dummy = NULL;

   to prevent compiler whinge in TRIO.C about uninitialised variables

- I had to add the following to nanoftp.c

     #if defined(VMS) || defined(__VMS)
       #define SOCKLEN_T unsigned int
     #endif

   This matches similar lines already added to nanohttp.c

- Several variables and function names exceed the 31 character limit
   used in VMS.  This leads to compiler warnings.  The 
solution adopted
   has been

   a) where variables or functions are defined, set up an ifdef on VMS
      to define a variable/function of a shorter name.  This 
may need to
      be done in the .h file, and in the implementation .c file

   b) use define statements to map the long name onto a shorter name.
      That way all future code can refer to the 
function/variable by the
      long name, reducing the need to add VMS-specific code 
everywhere.

   In the current distro, I had to do this for the following names

   in globals.c, parserinternals.c, globals.h, parser.h
     xmlSubstituteEntitiesDefaultValue
     xmlDoValidityCheckingDefaultValue

   in globals.c, globals.h
     __xmlDoValidityCheckingDefaultValue

   in xmlio.c, xmlio.h
     xmlRegisterDefaultInputCallbacks
     xmlRegisterDefaultOutputCallbacks

   in xpath.c and xpathinternals.h
     xmlXPathRegisteredVariablesCleanup

--
John A Fotheringham (Jaf)                      http://www.jafsoft.com/
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