readme.vms
1Issues in porting libxml to VMS
2===============================
3
4Here's a summary of the issues I encountered when building LIBXML under
5VMS. There was some VMS support in the version I got, but it was a little
6out of date with the result that some newer files had problems.
7
8I present this list "as is" to hopefully act as a guide to anyone having
9problems in the future.
10
11That's it. Good luck!
12
13John A Fotheringham (jaf@jafsoft.com)
14October 2001
15
16Updated October 2002 by Craig A Berry (craigberry@mac.com)
17
18Installation kit
19----------------
20
21- File attributes. Having downloaded essentially a Unix distribution, some
22 of the file attributes weren't correct... especially those in the [.VMS]
23 subdirectory. In EDT you could see line feeds and carriage returns as
24 <LF><CR> etc. To correct this use the command
25
26 $ set file <filespec> /attr=rfm=stm
27
28 This sets the record format to be "stream". Other variants may be used
29 instead depending on how you got the files onto your system. Files will
30 look okay in an EDT editor once the attributes are set. Without
31 this the command file may not run correctly, since it may be interpreted
32 as a single line.
33
34- VMS-specific files are in a [.VMS] directory. If you've found this file
35 then you already know this :-) This directory contains
36
37 BUILD_LIBXML.COM - a build command file, which I've radically re-worked
38 CONFIG.VMS - a configuration file to replace config.h
39
40- Don't execute BUILD_LIBXML.COM until you've done all the following
41
42 - read these notes
43 - reviewed the configuration section of BUILD_LIBXML.COM, and in particular
44 updated the module lists in line with MAKEFILE
45 - identified the location of the include files, so that you can manually
46 set the LIBXML logical if need be.
47 - re-read these notes :-p
48
49 instructions for all these steps are below.
50
51- the file [.vms]config.vms is used in lieu of a Configure-generated config.h.
52 This file contains a number of define statements that identify the software
53 options required under VMS
54
55- The include files are in a [.INCLUDE.LIBXML] subdirectory. You need
56 a logical "libxml" to point to this so that include statements of the
57 form
58
59 #include <libxml/parser.h>
60
61 will work correctly. The source files are mostly two levels above this
62 directory, although there are some .h files there as well.
63
64- The command file BUILD_LIBXML.COM will do the following
65
66 - setup some logicals
67 - set def to the source directory
68 - compile modules and place them into a LIBXML.OLB library
69 - compile and link a number of self-test programs
70 - compile and link a number of utilities and test programs
71 - set def back to the original directory (i.e. if it fails you might not be
72 where you started :-)
73
74 before running this command file review the configuration segment at
75 the top. In particular compare the lists of modules with those in the
76 most recent version of the Unix MAKEFILE. Instructions are contained
77 in the command file itself.
78
79 The command file will attempt to set two logicals
80
81 - xml_srcdir. The directory containing the source files
82 - libxml. The include file directory.
83
84 It attempts this by looking for modules globals.c and globals.h in
85 nearby directories. If this logic fails, you'll need to manually define
86 these logicals.
87
88
89The TRIO package
90----------------
91- A sub-package TRIO is used to provide some functions not naturally available
92 under VMS. These include support for infinite and undefined numbers,
93 and specialised print functions like "snprintf"
94
95 I had to make several changes to trionan.c in discussion with the author
96 (hopefully these are now included in the distro, so I won't list them here)
97
98 To build this software we need to add
99
100 /IEEE_MODE=UNDERFLOW_TO_ZERO/FLOAT=IEEE
101
102 to the compile command for xpath.c and trio.c, and to any main program
103 that uses this functionality. BUILD_LIBXML.COM should do this for you.
104
105- to build in trio support you need the define WITH_TRIO to be set. This
106 is done by default for VMS in xmlversion.h
107
108
109Compiler and linker errors
110--------------------------
111- the DEC C compiler may produce a number of warnings when compiling the
112 C code. These include
113
114 - Implicit function warnings. These indicate functions whose type is
115 not defined in a .h file. This will probably only happen if your
116 configuration is not correct (e.g. for "snprintf" if you haven't
117 edited xmlversion.h to set WITH_TRIO
118
119 - uninitialised variables. Not usually a problem. You can solve this
120 by editing the code to initialise the variables affected
121
122Changes made to the codebase
123----------------------------
124- I changed all dummy declarations in trio.c to be
125
126 va_list dummy = NULL;
127
128 to prevent compiler whinge in TRIO.C about uninitialised variables
129
130- I had to add the following to nanoftp.c
131
132 #if defined(VMS) || defined(__VMS)
133 #define SOCKLEN_T unsigned int
134 #endif
135
136 This matches similar lines already added to nanohttp.c
137
138- Several variables and function names exceed the 31 character limit
139 of the VMS linker. The solution adopted has been to use the
140 /NAMES=SHORTENED compiler option, which requires DEC/Compaq C 5.7
141 or later. For a complete list of the names that needed shortening
142 and the short names generated by the compiler, see [.vms]config.vms.
143
144