Last revised: 14-Dec-1995 by Charles Bailey bailey@genetics.upenn.edu The VMS port of Perl is still under development. At this time, the Perl binaries built under VMS handle internal operations properly, for the most part, as well as most of the system calls which have close equivalents under VMS. There are still some incompatibilities in process handling (e.g the fork/exec model for creating subprocesses doesn't do what you might expect under Unix), and there remain some file handling differences from Unix. Over the longer term, we'll try to get many of the useful VMS system services integrated as well, depending on time and people available. Of course, if you'd like to add something yourself, or join the porting team, we'd love to have you! The current sources and build procedures have been tested on a VAX using VAXC and on an AXP using DECC. If you run into problems with other compilers, please let us know. Note to DECC users: Some early versions of the DECCRTL contained a few bugs which affect Perl performance: - Newlines are lost on I/O through pipes, causing lines to run together. This shows up as RMS RTB errors when reading from a pipe. You can work around this by having one process write data to a file, and then having the other read the file, instead of the pipe. This is fixed in version 4 of DECC. - The modf() routine returns a non-integral value for some values above INT_MAX; the Perl "int" operator will return a non-integral value in these cases. This is fixed in version 4 of DECC. - On the AXP, if SYSNAM privilege is enabled, the CRTL chdir() routine changes the process default device and directory permanently, even though the call specified that the change should not persist after Perl exited. This is fixed by DEC CSC patch AXPACRT04_061. * Other software required At the moment, in addition to basic VMS, you'll need two things: - a C compiler: VAXC, DECC, or gcc for the VAX; DECC for the AXP - a make tool: DEC's MMS (version 2.6 or later) or the free analog MMK (available from ftp.spc.edu), or a standard make utility (e.g. GNU make, also available from ftp.spc.edu). In addition, you may include socket support if you have an IP stack running on your system. See the topic "Socket support" for more information. * Socket support Perl includes a number of IP socket routines among its builtin functions, which are available if you choose to compile Perl with socket support. Since IP networking is an optional addition to VMS, there are several different IP stacks available, so it's difficult to automate the process of building Perl with socket support in a way which will work on all systems. By default, Perl is built without IP socket support. If you define the macro SOCKET when invoking MMS, however, socket support will be included. As distributed, Perl for VMS includes support for the SOCKETSHR socket library, which is layered on MadGoat software's vendor-independent NETLIB interface. This provides support for all socket calls used by Perl except the [g|s]etnet*() routines, which are replaced for the moment by stubs which generate a fatal error if a Perl script attempts to call one of these routines. Both SOCKETSHR and NETLIB are available from MadGoat ftp sites, such as ftp.spc.edu or ftp.wku.edu. You can link Perl directly to your TCP/IP stack's library, *as long as* it supplies shims for stdio routines which will properly handle both sockets and normal file descriptors. This is necessary because Perl does not distinguish between the two, and will try to make normal stdio calls such as read() and getc() on socket file descriptors. If you'd like to link Perl directly to your IP stack, then make the following changes: - In Descrip.MMS, locate the section beginning with .ifdef SOCKET, and change the SOCKLIB macro so that it translates to the filespec of your IP stack's socket library. This will be added to the RTL options file. - Edit the file SockAdapt.H in the [.VMS] subdirectory so that it includes the Socket.H, In.H, Inet.H, NetDb.H, and, if necessary, Errno.H header files for your IP stack, or so that it declares the standard TCP/IP constants and data structures appropriately. (See the distributed copy of SockAdapt.H for a collection of the structures needed by Perl itself, and [.ext.Socket]Socket.xs for a list of the constants used by the Socket extension, if you elect to built it.) You should also define any logical names necessary for your C compiler to find these files before invoking MM[KS] to build Perl. - Edit the file SockAdapt.C in the [.VMS] subdirectory so that it contains routines which substitute for any IP library routines required by Perl which your IP stack does not provide. This may require a little trial and error; we'll try to compile a complete list soon of socket routines required by Perl. * Building Perl under VMS Since you're reading this, presumably you've unpacked the Perl distribution into its directory tree, in which you will find a [.vms] subdirectory below the directory in which this file is found. If this isn't the case, then you'll need to unpack the distribution properly, or manually edit Descrip.MMS or the VMS Makefile to alter directory paths as necessary. (I'd advise using the `normal' directory tree, at least for the first time through.) This subdirectory contains several files, among which are the following: Config.VMS - A template Config.H set up for VMS. Descrip.MMS - The MMS/MMK dependency file for building Perl GenConfig.Pl - A Perl script to generate Config.SH retrospectively from Config.VMS, since the Configure shell script which normally generates Config.SH doesn't run under VMS. GenOpt.Com - A little DCL procedure used to write some linker options files, since not all make utilities can do this easily. Gen_ShrFls.Pl - A Perl script which generates linker options files and MACRO declarations for PerlShr.Exe. Makefile - The make dependency file for building Perl MMS2Make.Pl - A Perl script used to generate Makefile from Descrip.MMS PerlVMS.pod - Documentation for VMS-specific behavior of Perl Perly_[CH].VMS - Versions of the byacc output from Perl's grammar, modified to include VMS-specific C compiler options SockAdapt.[CH] - C source code used to integrate VMS TCP/IP support Test.Com - DCL driver for Perl regression tests VMSish.H - C header file containing VMS-specific definitions VMS.C - C source code for VMS-specific routines VMS_Yfix.Pl - Perl script to convert Perly.[CH] to Perly_[CH].VMS WriteMain.Pl - Perl script to generate Perlmain.C The [.Ext...] directories contain VMS-specific extensions distributed with Perl. There may also be other files in [.VMS...] pertaining to features under development; for the most part, you can ignore them. Config.VMS and Decrip.MMS/Makefile are set up to build a version of Perl which includes all features known to work when this release was assembled. If you have code at your site which would support additional features (e.g. emulation of Unix system calls), feel free to make the appropriate changes to these files. (Note: Do not use or edit config.h in the main Perl source directory; it is superseded by the current Config.VMS during the build.) You may also wish to make site-specific changes to Descrip.MMS or Makefile to reflect local conventions for naming of files, etc. There are several pieces of system-specific information which become part of the Perl Config extension. Under VMS, the data for Config are generated by the script GenConfig.Pl in the [.VMS] subdirectory. It tries to ascertain the necessary information from various files, or from the system itself, and generally does the right thing. There is a list of hard-coded values at the end of this script which specifies items that are correct for most VMS systems, but may be incorrect for you, if your site is set up in an unusual fashion. If you're familiar with Perl's Config extension, feel free to edit these values as necessary. If this doesn't mean much to you, don't worry -- the information is probably correct, and even if it's not, none of these parameters affect your ability to build or run Perl. You'll only get the wrong answer if you ask for it specifically from Config. Examine the information at the beginning of Descrip.MMS for information about specifying alternate C compilers or building a version of Perl with debugging support. For instance, if you want to use DECC, you'll need to include the /macro="decc=1" qualifier to MMS (If you're using make, these options are not supported.) If you're on an AXP system, define the macro __AXP__ (MMK does this for you), and DECC will automatically be selected. To start the build, set default to the main source directory. Since Descrip.MMS assumes that VMS commands have their usual meaning, and makes use of command-line macros, you may want to be certain that you haven't defined DCL symbols which would interfere with the build. Then, if you are using MMS or MMK, say $ MMS/Descrip=[.VMS] ! or MMK (N.B. If you are using MMS, you must use version 2.6 or later; a bug in earlier versions produces malformed cc command lines.) If you are using a version of make, say $ Make -f [.VMS]Makefile Note that the Makefile doesn't support conditional compilation, is set up to use VAXC on a VAX, and does not include socket support. You can either edit the Makefile by hand, using Descrip.MMS as a guide, or use the Makefile to build Miniperl.Exe, and then run the Perl script MMS2Make.pl, found in the [.VMS] subdirectory, to generate a new Makefile with the options appropriate to your site. Note for sites using DECC: A bug in some early versions of the DECC RTL on the AXP causes newlines to be lost when writing to a pipe. This causes Gen_ShrFls.pl to fail, since it can't read the preprocessor output to identify global variables and routines. A different bug in the DECC preprocessor itself for some patched versions of DECC 4.0 on the VAX also makes it impossible for Gen_ShrFls.pl to parse the preprocessor output. In either case, the problem is generally manifested as missing global symbols when linking PerlShr.Exe or Perl.Exe. You can work around this problem by defining the macro DECC_PIPES_BROKEN when you invoke MMS or MMK. This will build the following files: Miniperl.Exe - a stand-alone version of without any extensions. Miniperl has all the intrinsic capabilities of Perl, but cannot make use of the DynaLoader or any extensions which use XS code. PerlShr.Exe - a shareable image containing most of Perl's internal routines and global variables. Perl.Exe is linked to this image, as are all dynamic extensions, so everyone's using the same set of global variables and routines. Perl.Exe - the main Perl executable image. It's contains the main() routine, plus code for any statically linked extensions. PerlShr_Attr.Opt - A linker options file which specifies psect attributes matching those in PerlShr.Exe. It should be used when linking images against PerlShr.Exe PerlShr_Bld.Opt - A linker options file which specifies various things used to build PerlShr.Exe. It should be used when rebuilding PerlShr.Exe via MakeMaker-produced Descrip.MMS files for static extensions. [.Lib]Config.pm - the Perl extension which saves configuration information about Perl and your system. [.Lib]DynaLoader.pm - The Perl extension which performs dynamic linking of shareable images for extensions. Several subdirectories under [.Lib] containing preprocessed files or site-specific files. There are, of course, a number of other files created for use during the build. Once you've got the binaries built, you may wish to `build' the `tidy' or `clean' targets to remove extra files. * Installing Perl once it's built Once the build is complete, you'll need to do the following: - Put PerlShr.Exe in a common directory, and make it world-readable. If you place it in a location other than Sys$Share, you'll need to define the logical name PerlShr to point to the image. - Put Perl.Exe in a common directory, and make it world-executable. - Define a foreign command to invoke Perl, using a statement like $ Perl == "$dev:[dir]Perl.Exe" - Create a world-readable directory tree for Perl library modules, scripts, and what-have-you, and define PERL_ROOT as a rooted logical name pointing to the top of this tree (i.e. if your Perl files were going to live in DKA1:[Util.Perl5...], then you should $ Define/Translation=Concealed Perl_Root DKA1:[Util.Perl5.] (Be careful to follow the rules for rooted logical names; in particular, remember that a rooted logical name cannot have as its device portion another rooted logical name - you've got to supply the actual device name and directory path to the root directory.) - Place the files from the [.lib...] directory tree in the distribution package into a [.lib...] directory tree off the root directory described above. - Most of the Perl documentation lives in the [.pod] subdirectory, and is written in a simple markup format which can be easily read. In this directory as well are pod2man and pod2html translators to reformat the docs for common display engines; a pod2hlp translator is under development. Information on Perl can also be gleaned from the files in the [.doc] subdirectory (internals documents and summaries of changes), and from the test scripts in the [.t...] subdirectories. For this reason, you may wish to copy these subtrees into directories under Perl_Root. That's it. * For more information If you're interested in more information on Perl in general, consult the Usenet newsgroups comp.lang.perl.announce and comp.lang.perl.misc. The FAQ for these groups provides pointers to other online sources of information, as well as books describing Perl in depth. If you're interested in up-to-date information on Perl development and internals, you might want to subscribe to the perl5-porters mailing list. You can do this by sending a message to perl5-porters-request@nicoh.com, containing the single line subscribe perl5-porters This is a moderately high-volume list at the moment (25-50 messages/day). If you're interested in ongoing information about the VMS port, you can subscribe to the VMSperl mailing list by sending a request to bailey@genetics.upenn.edu (it's to a human, not a list server - this is a small operation at the moment). And, as always, we welcome any help or code you'd like to offer - you can send mail to bailey@genetics.upenn.edu or directly to the VMSperl list at vmsperl@genetics.upenn.edu. Finally, if you'd like to try out the latest changes to VMS Perl, you can retrieve a test distribution kit by anonymous ftp from genetics.upenn.edu, in the file [.perl5]perl5_ppp_yymmddx.zip, where "ppp" is the current Perl patchlevel, and "yymmddx" is a sequence number indicating the date that particular kit was assembled. In order to make retrieval convenient, this kit is also available by the name Perl5_VMSTest.Zip. These test kits contain "unofficial" patches from the perl5-porters group, test patches for important bugs, and VMS-specific fixes and improvements which have occurred since the last Perl release. Most of these changes will be incorporated in the next release of Perl, but until Larry Wall's looked at them and said they're OK, none of them should be considered official. Good luck using Perl. Please let us know how it works for you - we can't guarantee that we'll be able to fix bugs quickly, but we'll try, and we'd certainly like to know they're out there. * Acknowledgements There are, of course, far too many people involved in the porting and testing of Perl to mention everyone who deserves it, so please forgive us if we've missed someone. That said, special thanks are due to the following: Tim Adye for the VMS emulations of getpw*() David Denholm for extensive testing and provision of pipe and SocketShr code, Mark Pizzolato for the getredirection() code Rich Salz for readdir() and related routines Denis Haskin for work on a pod-to-hlp translator for the Perl documentation Richard Dyson and Kent Covert for additional testing on the AXP. and to the entire VMSperl group for useful advice and suggestions. In addition the perl5-porters, especially Andy Dougherty and Tim Bunce , deserve credit for their creativity and willingness to work with the VMS newcomers. Finally, the greatest debt of gratitude is due to Larry Wall , for having the ideas which have made our sleepless nights possible. Thanks, The VMSperl group