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diff --git a/vms/perlvms.pod b/vms/perlvms.pod index 77ec503f61..e7f811e0a8 100644 --- a/vms/perlvms.pod +++ b/vms/perlvms.pod @@ -1,84 +1,203 @@ -=head1 Notes on Perl5 for VMS +=head1 Notes on Perl 5 for VMS -Gathered below are notes describing details of perl 5's -behavior on VMS. They are a supplement to the regular perl 5 -documentation, so we have focussed on the ways in which perl -5 functions differently under VMS thatn it does under Unix, -and on teh interactions between perl and the rest of the +Gathered below are notes describing details of Perl 5's +behavior on VMS. They are a supplement to the regular Perl 5 +documentation, so we have focussed on the ways in which Perl +5 functions differently under VMS than it does under Unix, +and on the interactions between Perl and the rest of the operating system. We haven't tried to duplicate complete -descriptions of perl5 features from the main perl +descriptions of Perl features from the main Perl documentation, which can be found in the F<[.pod]> -subdirectory of the perl 5 distribution. +subdirectory of the Perl distribution. We hope these notes will save you from confusion and lost -sleep when writing perl scripts on VMS. If you find we've +sleep when writing Perl scripts on VMS. If you find we've missed something you think should appear here, please don't hesitate to drop a line to vmsperl@genetics.upenn.edu. -=head2 Installation - -Directions for building and installing perl 5 can be found in +=head1 Organization of Perl + +=head2 Perl Images + +During the installation process, three Perl images are produced. +F<Miniperl.Exe> is an executable image which contains all of +the basic functionality of Perl, but cannot take advantage of +Perl extensions. It is used to generate several files needed +to build the complete Perl and various extensions. Once you've +finished installing Perl, you can delete this image. + +Most of the complete Perl resides in the shareable image +F<PerlShr.Exe>, which provides a core to which the Perl executable +image and all Perl extensions are linked. You should place this +image in F<Sys$Share>, or define the logical name F<PerlShr> to +translate to the full file specification of this image. It should +be world readable. (Remember that if a user has execute only access +to F<PerlShr>, VMS will treat it as if it were a privileged shareable +image, and will therefore require all downstream shareable images to be +INSTALLed, etc.) + + +Finally, F<Perl.Exe> is an executable image containing the main +entry point for Perl, as well as some initialization code. It +should be placed in a public directory, and made world executable. +In order to run Perl with command line arguments, you should +define a foreign command to invoke this image. + +=head2 Perl Extensions + +Perl extensions are packages which provide both XS and Perl code +to add new functionality to perl. (XS is a meta-language which +simplifies writing C code which interacts with Perl, see +L<perlapi> for more details.) The Perl code for an +extension is treated like any other library module - it's +made available in your script through the appropriate +C<use> or C<require> statement, and usually defines a Perl +package containing the extension. + +The portion of the extension provided by the XS code may be +connected to the rest of Perl in either of two ways. In the +B<static> configuration, the object code for the extension is +linked directly into F<PerlShr.Exe>, and is initialized whenever +Perl is invoked. In the B<dynamic> configuration, the extension's +machine code is placed into a separate shareable image, which is +mapped by Perl's DynaLoader when the extension is C<use>d or +C<require>d in your script. This allows you to maintain the +extension as a separate entity, at the cost of keeping track of the +additional shareable image. Most extensions can be set up as either +static or dynamic. + +The source code for an extension usually resides in its own +directory. At least three files are generally provided: +I<Extshortname>F<.xs> (where I<Extshortname> is the portion of +the extension's name following the last C<::>), containing +the XS code, I<Extshortname>F<.pm>, the Perl library module +for the extension, and F<Makefile.PL>, a Perl script which uses +the C<MakeMaker> library modules supplied with Perl to generate +a F<Descrip.MMS> file for the extension. + +=head3 Installing static extensions + +Since static extensions are incorporated directly into +F<PerlShr.Exe>, you'll have to rebuild Perl to incorporate a +new extension. You should edit the main F<Descrip.MMS> or F<Makefile> +you use to build Perl, adding the extension's name to the C<ext> +macro, and the extension's object file to the C<extobj> macro. +You'll also need to build the extension's object file, either +by adding dependencies to the main F<Descrip.MMS>, or using a +separate F<Descrip.MMS> for the extension. Then, rebuild +F<PerlShr.Exe> to incorporate the new code. + +Finally, you'll need to copy the extension's Perl library +module to the F<[.>I<Extname>F<]> subdirectory under one +of the directories in C<@INC>, where I<Extname> is the name +of the extension, with all C<::> replaced by C<.> (e.g. +the library module for extension Foo::Bar would be copied +to a F<[.Foo.Bar]> subdirectory). + +=head3 Installic dynamic extensions + +First, you'll need to compile the XS code into a shareable image, +either by hand or using the F<Descrip.MMS> supplied with the +extension. If you're building the shareable image by hand, please +note the following points: + - The shareable image must be linked to F<PerlShr.Exe>, so it + has access to Perl's global variables and routines. In + order to specify the correct attributes for psects in + F<PerlShr.Exe>, you should include the linker options file + F<PerlShr_Attr.Opt> in the Link command. (This file is + generated when F<PerlShr.Exe> is built, and is found in the + main Perl source directory. + - The entry point for the C<boot_>I<Extname> routine (where + I<Extname> is the name of the extension, with all C<::> + replaced by C<__>) must be a universal symbol. No other + universal symbols are required to use the shareable image + with Perl, though you may want to include additional + universal symbols if you plan to share code or data among + different extensions. +The shareable image can be placed in any of several locations: + - the F<[.Auto.>I<Extname>F<]> subdirectory of one of + the directories in C<@INC>, where I<Extname> is the + name of the extension, with each C<::> translated to C<.> + (e.g. for extension Foo::Bar, you would use the + F<[.Auto.Foo.Bar]> subdirectory), or + - one of the directories in C<@INC>, or + - a directory which the extensions Perl library module + passes to the DynaLoader when asking it to map + the shareable image, or + - F<Sys$Share> or F<Sys$Library>. +If the shareable image isn't in any of these places, you'll need +to define a logical name I<Extshortname>, where I<Extshortname> +is the portion of the extension's name after the last C<::>, which +translates to the full file specification of the shareable image. + +Once you've got the shareable image set up, you should copy the +extension's Perl library module to the appropriate library directory +(see the section above on installing static extensions). + +=head1 Installation + +Directions for building and installing Perl 5 can be found in the file F<ReadMe.VMS> in the main source directory of the -perl5 distribution.. +Perl distribution.. -=head2 File specifications +=head1 File specifications -We have tried to make perl aware of both VMS-style and Unix- +We have tried to make Perl aware of both VMS-style and Unix- style file specifications wherever possible. You may use either style, or both, on the command line and in scripts, but you may not combine the two styles within a single fle specfication. Filenames are, of course, still case- -insensitive. For consistency, most perl5 routines return +insensitive. For consistency, most Perl routines return filespecs using lower case latters only, regardless of the case used in the arguments passed to them. (This is true -only when running under VMS; perl5 respects the case- +only when running under VMS; Perl respects the case- sensitivity of OSs like Unix.) -We've tried to minimize the dependence of perl library +We've tried to minimize the dependence of Perl library modules on Unix syntax, but you may find that some of these, as well as some scripts written for Unix systems, will require that you use Unix syntax, since they will assume that '/' is the directory separator, etc. If you find instances -of this in the perl distribution itself, please let us know, +of this in the Perl distribution itself, please let us know, so we can try to work around them. -=head2 Command line redirection +=head1 Command line redirection Perl for VMS supports redirection of input and output on the command line, using a subset of Bourne shell syntax: <F<file> reads stdin from F<file>, >F<file> writes stdout to F<file>, >>F<file> appends stdout to F<file>, - 2>F<file> wrtits stderr to F<file>, and + 2>F<file> writes stderr to F<file>, and 2>>F<file> appends stderr to F<file>. In addition, output may be piped to a subprocess, using the character '|'. Anything after this character on the command line is passed to a subprocess for execution; the subprocess -takes the output of perl as its input. +takes the output of Perl as its input. Finally, if the command line ends with '&', the entire command is run in the background as an asynchronous subprocess. -=head2 Pipes +=head1 Pipes -Input and output pipes to perl filehandles are supported; the +Input and output pipes to Perl filehandles are supported; the "file name" is passed to lib$spawn() for asynchronous execution. You should be careful to close any pipes you have -opened in a perl script, lest you leave any "orphaned" -subprocesses around when perl exits. +opened in a Perl script, lest you leave any "orphaned" +subprocesses around when Perl exits. You may also use backticks to invoke a DCL subprocess, whose output is used as the return value of the expression. The string between the backticks is passed directly to lib$spawn -as the command to execute. In this case, perl will wait for +as the command to execute. In this case, Perl will wait for the subprocess to complete before continuing. -=head2 Wildcard expansion +=head1 Wildcard expansion File specifications containing wildcards are allowed both on -the command line and within perl globs (e.g. <C<*.c>>). If +the command line and within Perl globs (e.g. <C<*.c>>). If the wildcard filespec uses VMS syntax, the resultant filespecs will follow VMS syntax; if a Unix-style filespec is passed in, Unix-style filespecs will be returned.. @@ -99,7 +218,14 @@ the behavior of glob expansion performed by Unix shells.) Similarly, the resultant filespec will the file version only if one was present in the input filespec. -=head2 %ENV +=head1 PERL5LIB and PERLLIB + +The PERL5LIB and PERLLIB logical names work as +documented L<perl>, except that the element +separator is '|' instead of ':'. The directory +specifications may use either VMS or Unix syntax. + +=head1 %ENV Reading the elements of the %ENV array returns the translation of the logical name specified by the key, @@ -110,30 +236,31 @@ variables" of the same names. The key C<default> returns the current default device and directory specification. Setting an element of %ENV defines a supervisor-mode logical -name in the process logical name table. B<Undef>ing or -B<delete>ing an element of %ENV deletes the equivalent user- +name in the process logical name table. C<Undef>ing or +C<delete>ing an element of %ENV deletes the equivalent user- mode or supervisor-mode logical name from the process logical -name table. If you use B<undef>, the %ENV element remains -empty. If you use B<delete>, another attempt is made at +name table. If you use C<undef>, the %ENV element remains +empty. If you use C<delete>, another attempt is made at logical name translation after the deletion, so an inner-mode logical name or a name in another logical name table will replace the logical name just deleted. In all operations on %ENV, the key string is treated as if it were entirely uppercase, regardless of the case actually -specified in the perl expression. +specified in the Perl expression. -=head2 Perl functions +=head1 Perl functions As of the time this document was last revised, the following -perl functions were implemented in the VMS port of perl +Perl functions were implemented in the VMS port of Perl (functions marked with * are discussed in more detail below): file tests*, abs, alarm, atan, binmode*, bless, caller, chdir, chmod, chown, chomp, chop, chr, close, closedir, cos, defined, delete, die, do, - each, eof, eval, exec*, exists, exit, exp, fileno, - fork*, getc, glob, goto, grep, hex, import, index, + each, endpwent, eof, eval, exec*, exists, exit, + exp, fileno, fork*, getc, getpwent*, getpwnam*, + getpwuid*, glob, goto, grep, hex, import, index, int, join, keys, kill, last, lc, lcfirst, length, local, localtime, log, m//, map, mkdir, my, next, no, oct, open, opendir, ord, pack, pipe, pop, pos, @@ -141,12 +268,12 @@ perl functions were implemented in the VMS port of perl quotemeta, rand, read, readdir, redo, ref, rename, require, reset, return, reverse, rewinddir, rindex, rmdir, s///, scalar, seek, seekdir, select(internal)*, - shift, sin, sleep, sort, splice, split, sprintf, - sqrt, srand, stat, study, substr, sysread, system*, - syswrite, tell, telldir, tie, time, times*, tr///, - uc, ucfirst, umask, undef, unlink, unpack, untie, - unshift, use, values, vec, wait, wantarray, warn, - write, y/// + setpwent, shift, sin, sleep, sort, splice, split, + sprintf, sqrt, srand, stat, study, substr, sysread, + system*, syswrite, tell, telldir, tie, time, times*, + tr///, uc, ucfirst, umask, undef, unlink, unpack, + untie, unshift, use, utime*, values, vec, wait, + waitpid*, wantarray, warn, write, y/// The following functions were not implemented in the VMS port, and calling them produces a fatal error (usually) or @@ -154,18 +281,16 @@ undefined behavior (rarely, we hope): chroot, crypt, dbmclose, dbmopen, dump, fcntl, flock, getlogin, getpgrp, getppid, getpriority, - getpwent, getgrent, kill, getgrgid, getgrnam, - getpwnam, getpwuid, setpwent, setgrent, - endpwent, endgrent, gmtime, ioctl, link, lstst, - msgctl, msgget, msgsend, msgrcv, readlink, + getgrent, kill, getgrgid, getgrnam, setgrent, + endgrent, gmtime, ioctl, link, lstst, msgctl, + msgget, msgsend, msgrcv, readlink, select(system call), semctl, semget, semop, setpgrp, setpriority, shmctl, shmget, shmread, - shmwrite, socketpair, symlink, syscall, truncate, - utime, waitpid + shmwrite, socketpair, symlink, syscall, truncate The following functions may or may not be implemented, depending on what type of socket support you've built into -your copy of perl: +your copy of Perl: accept, bind, connect, getpeername, gethostbyname, getnetbyname, getprotobyname, getservbyname, gethostbyaddr, getnetbyaddr, @@ -179,86 +304,136 @@ your copy of perl: =item File tests -The tests -b, -B, -c, -C, -d, -e, -f, -o, -M, -s, -S, -t, -T, -and -z work as advertised. The return values for -r, -w, and --x tell you whether you can actually access the file; this -may mot reflect the UIC-based file protections. Since real -and effective UIC don't differ under VMS, -O, -R, -W, and -X -are equivalent to -o, -r, -w, and -x. Similarly, several -other tests, including -A, -g, -k, -l,-p, and -u, aren't -particularly meaningful under VMS, and the values returned by -these tests reflect whatever your CRTL stat() routine does to -the equivalent bits in the st_mode field. - -=item binmode - -The B<binmode> operator has no effect under VMS. It will +The tests C<-b>, C<-B>, C<-c>, C<-C>, C<-d>, C<-e>, C<-f>, +C<-o>, C<-M>, C<-s>, C<-S>, C<-t>, C<-T>, and C<-z> work as +advertised. The return values for C<-r>, C<-w>, and C<-x> +tell you whether you can actually access the file; this may +not reflect the UIC-based file protections. Since real and +effective UIC don't differ under VMS, C<-O>, C<-R>, C<-W>, +and C<-X> are equivalent to C<-o>, C<-r>, C<-w>, and C<-x>. +Similarly, several other tests, including C<-A>, C<-g>, C<-k>, +C<-l>, C<-p>, and C<-u>, aren't particularly meaningful under +VMS, and the values returned by these tests reflect whatever +your CRTL C<stat()> routine does to the equivalent bits in the +st_mode field. Finally, C<-d> returns true if passed a device +specification without an explicit directory (e.g. C<DUA1:>), as +well as if passed a directory. + +=item binmode FILEHANDLE + +The C<binmode> operator has no effect under VMS. It will return TRUE whenever called, but will not affect I/O operations on the filehandle given as its argument. -=item exec +=item exec LIST -The B<exec> operator behaves in one of two different ways. -If called after a call to B<fork>, it will invoke the CRTL -L<execv()> routine, passing its arguments to the subprocess -created by B<fork> for execution. In this case, it is -subject to all limitation that affect L<execv>. (In +The C<exec> operator behaves in one of two different ways. +If called after a call to C<fork>, it will invoke the CRTL +C<execv()> routine, passing its arguments to the subprocess +created by C<fork> for execution. In this case, it is +subject to all limitations that affect C<execv()>. (In particular, this usually means that the command executed in the subprocess must be an image compiled from C source code, and that your options for passing file descriptors and signal handlers to the subprocess are limited.) -If the call to B<exec> does not follow a call to B<fork>, it -will cause perl to exit, and to invoke the command given as -an argument to B<exec> via lib$do_command. If the argument +If the call to C<exec> does not follow a call to C<fork>, it +will cause Perl to exit, and to invoke the command given as +an argument to C<exec> via C<lib$do_command>. If the argument begins with a '$' (other than as part of a filespec), then it is executed as a DCL command. Otherwise, the first token on the command line is treated as the filespec of an image to run, and an attempt is made to invoke it (using F<.Exe> and the process defaults to expand the filespec) and pass the -rest of B<exec>'s argument to it as parameters. +rest of C<exec>'s argument to it as parameters. -You can use B<exec> in both ways within the same script, as -long as you call B<fork> and B<exec> in pairs. Perl only -keeps track of whether B<fork> has been called since the last -call to B<exec> when figuring out what to do, so multiple -calls to B<fork> do not generate multiple levels of "fork -context". +You can use C<exec> in both ways within the same script, as +long as you call C<fork> and C<exec> in pairs. Perl +keeps track of how many times C<fork> and C<exec> have been +called, and will call the CRTL C<execv()> routine if there have +previously been more calls to C<fork> than to C<exec>. =item fork -The B<fork> operator works in the same way as the CRTL -L<fork()> routine, which is quite different under VMS than -under Unix. Sepcifically, while B<fork> returns 0 after it -is called and the subprocess PID after B<exec> is called, in +The C<fork> operator works in the same way as the CRTL +C<vfork()> routine, which is quite different under VMS than +under Unix. Specifically, while C<fork> returns 0 after it +is called and the subprocess PID after C<exec> is called, in both cases the thread of execution is within the parent process, so there is no opportunity to perform operations in -the subprocess before calling B<exec>. +the subprocess before calling C<exec>. -In general, the use of B<fork> and B<exec> to create +In general, the use of C<fork> and C<exec> to create subprocess is not recommended under VMS; wherever possible, -use the B<system> operator or piped filehandles instead. +use the C<system> operator or piped filehandles instead. + +=item getpwent +=item getpwnam +=item getpwuid + +These operators obtain the information described in L<perlfunc>, +if you have the privileges necessary to retrieve the named user's +UAF information via C<sys$getuai>. If not, then only the C<$name>, +C<$uid>, and C<$gid> items are returned. The C<$dir> item contains +the login directory in VMS syntax, while the C<$comment> item +contains the login directory in Unix syntax. The C<$gcos> item +contains the owner field from the UAF record. The C<$quota> +item is not used. -=item system +=item stat EXPR -The B<system> operator creates a subprocess, and passes its +Since VMS keeps track of files according to a different scheme +than Unix, it's not really possible to represent the file's ID +in the C<st_dev> and C<st_ino> fields of a C<struct stat>. Perl +tries its best, though, and the values it uses are pretty unlikely +to be the same for two different files. We can't guarantee this, +though, so caveat scriptor. + +=item system LIST + +The C<system> operator creates a subprocess, and passes its arguments to the subprocess for execution as a DCL command. Since the subprocess is created directly via lib$spawn, any -valid DCL command string may be specified. Perl waits for -the subprocess to complete before continuing execution in the -current process. +valid DCL command string may be specified. If LIST consists +of the empty string, C<system> spawns an interactive DCL subprocess, +in the same fashion as typiing B<SPAWN> at the DCL prompt. +Perl waits for the subprocess to complete before continuing +execution in the current process. =item times -The array returned by the B<times> operator is divided up -according to the same rules the CRTL L<times()> routine. +The array returned by the C<times> operator is divided up +according to the same rules the CRTL C<times()> routine. Therefore, the "system time" elements will always be 0, since there is no difference between "user time" and "system" time under VMS, and the time accumulated by subprocess may or may not appear separately in the "child time" field, depending on -whether L<times> keeps track of subprocesses separately. +whether L<times> keeps track of subprocesses separately. Note +especially that the VAXCRTL (at least) keeps track only of +subprocesses spawned using L<fork> and L<exec>; it will not +accumulate the times of suprocesses spawned via pipes, L<system>, +or backticks. + +=item utime LIST + +Since ODS-2, the VMS file structure for disk files, does not keep +track of access times, this operator changes only the modification +time of the file (VMS revision date). + +=item waitpid PID,FLAGS + +If PID is a subprocess started by a piped L<open>, C<waitpid> +will wait for that subprocess, and return its final +status value. If PID is a subprocess created in some other way +(e.g. SPAWNed before Perl was invoked), or is not a subprocess of +the current process, C<waitpid> will check once per second whether +the process has completed, and when it has, will return 0. (If PID +specifies a process that isn't a subprocess of the current process, +and you invoked Perl with the C<-w> switch, a warning will be issued.) + +The FLAGS argument is ignored in all cases. -=head2 Revision date +=head1 Revision date -This document was last updated on 16-Oct-1994, for perl 5, +This document was last updated on 16-Dec-1994, for Perl 5, patchlevel 0. |