X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=vms%2Fperlvms.pod;h=35776a49d4406046dc4931e79e66ace16cb5929c;hb=d925a710473da185a5589455ee8d26c4862a29ad;hp=377d97f6feb4182b979af41b30b554bc54267d7b;hpb=a5f75d667838e8e7bb037880391f5c44476d33b4;p=p5sagit%2Fp5-mst-13.2.git diff --git a/vms/perlvms.pod b/vms/perlvms.pod index 377d97f..35776a4 100644 --- a/vms/perlvms.pod +++ b/vms/perlvms.pod @@ -17,7 +17,13 @@ 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 missed something you think should appear here, please don't -hesitate to drop a line to vmsperl@genetics.upenn.edu. +hesitate to drop a line to vmsperl@perl.org. + +=head1 Installation + +Directions for building and installing Perl 5 can be found in +the file F in the main source directory of the +Perl distribution.. =head1 Organization of Perl Images @@ -52,7 +58,7 @@ define a foreign command to invoke this image. 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 for more details.) The Perl code for an +L 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 or C statement, and usually defines a Perl @@ -116,7 +122,7 @@ I The procedure by which extensions are built and tested creates several levels (at least 4) under the directory in which the extension's source files live. For this reason, you shouldn't nest the source directory -too deeply in your directory structure, lest you eccedd RMS' +too deeply in your directory structure, lest you exceed RMS' maximum of 8 levels of subdirectory in a filespec. (You can use rooted logical names to get another 8 levels of nesting, if you can't place the files near the top of @@ -134,13 +140,16 @@ be added to the linker options file F produced during the build process for the Perl extension. By default, the shareable image for an extension is placed -in the F<[.Lib.Auto.I.I]> directory of the +F<[.lib.site_perl.auto>I.IF<]> directory of the installed Perl directory tree (where I is F or F, and I is the name of the extension, with -each C<::> translated to C<.>). However, it can be manually -placed in any of several locations: - - the F<[.Lib.Auto.I]> subdirectory of one of - the directories in C<@INC>, or +each C<::> translated to C<.>). (See the MakeMaker documentation +for more details on installation options for extensions.) +However, it can be manually placed in any of several locations: + - the F<[.Lib.Auto.>II<$PVers>IF<]> subdirectory + of one of the directories in C<@INC> (where I + is the version of Perl you're using, as supplied in C<$]>, + with '.' converted to '_'), 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 @@ -151,74 +160,47 @@ to define a logical name I, where I is the portion of the extension's name after the last C<::>, which translates to the full file specification of the shareable image. -=head1 Installation - -Directions for building and installing Perl 5 can be found in -the file F in the main source directory of the -Perl distribution.. +=head1 File specifications -=head1 File specifications +=head2 Syntax 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 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; Perl respects the case- -sensitivity of OSs like Unix.) +but you may not combine the two styles within a single file +specification. VMS Perl interprets Unix pathnames in much +the same way as the CRTL (I the first component of +an absolute path is read as the device name for the +VMS file specification). There are a set of functions +provided in the C package for explicit +interconversion between VMS and Unix syntax; its +documentation provides more details. + +Filenames are, of course, still case-insensitive. For +consistency, most Perl routines return filespecs using +lower case letters only, regardless of the case used in +the arguments passed to them. (This is true only when +running under VMS; Perl respects the case-sensitivity +of OSs like Unix.) 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 +'/' is the directory separator, I If you find instances of this in the Perl distribution itself, please let us know, so we can try to work around them. -=head1 Command line redirection - -Perl for VMS supports redirection of input and output on the -command line, using a subset of Bourne shell syntax: - reads stdin from F, - >F writes stdout to F, - >>F appends stdout to F, - 2>F writes stderr to F, and - 2>>F appends stderr to F. - -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. - -Finally, if the command line ends with '&', the entire -command is run in the background as an asynchronous -subprocess. - -=head1 Pipes - -Input and output pipes to Perl filehandles are supported; the -"file name" is passed to lib$spawn() for asynchronous -execution. You should be careful to close any pipes you have -opened in a Perl script, lest you leave any "orphaned" -subprocesses around when Perl exits. - -You may also use backticks to invoke a DCL subprocess, whose -output is used as the return value of the expression. The -string between the backticks is passed directly to lib$spawn -as the command to execute. In this case, Perl will wait for -the subprocess to complete before continuing. - -=head1 Wildcard expansion +=head2 Wildcard expansion File specifications containing wildcards are allowed both on -the command line and within Perl globs (e.g. >). If +the command line and within Perl globs (e.g. C*.cE>). 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.. +passed in, Unix-style filespecs will be returned. +In both cases, VMS wildcard expansion is performed. (csh-style +wildcard expansion is available if you use C.) If the wildcard filespec contains a device or directory specification, then the resultant filespecs will also contain a device and directory; otherwise, device and directory @@ -232,15 +214,105 @@ of C<[.t]*.*> will yield filespecs like yield filespecs like "t/base.dir". (This is done to match 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. +Similarly, the resultant filespec will contain the file version +only if one was present in the input filespec. + +=head2 Pipes + +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. + +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 handled as if it were the +argument to the C operator (see below). In this case, +Perl will wait for the subprocess to complete before continuing. =head1 PERL5LIB and PERLLIB -The PERL5LIB and PERLLIB logical names work as -documented L, except that the element -separator is '|' instead of ':'. The directory -specifications may use either VMS or Unix syntax. +The PERL5LIB and PERLLIB logical names work as documented in L, +except that the element separator is '|' instead of ':'. The +directory specifications may use either VMS or Unix syntax. + +=head1 Command line + +=head2 I/O redirection and backgrounding + +Perl for VMS supports redirection of input and output on the +command line, using a subset of Bourne shell syntax: + +=over + +=item * + +Cfile> reads stdin from C, + +=item * + +Cfile> writes stdout to C, + +=item * + +CEfile> appends stdout to C, + +=item * + +C<2Efile> writes stderr to C, and + +=item * + +C<2EEfile> appends stderr to C. + +=back + +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. + +Finally, if the command line ends with '&', the entire +command is run in the background as an asynchronous +subprocess. + +=head2 Command line switches + +The following command line switches behave differently under +VMS than described in L. Note also that in order +to pass uppercase switches to Perl, you need to enclose +them in double-quotes on the command line, since the CRTL +downcases all unquoted strings. + +=over 4 + +=item -i + +If the C<-i> switch is present but no extension for a backup +copy is given, then inplace editing creates a new version of +a file; the existing copy is not deleted. (Note that if +an extension is given, an existing file is renamed to the backup +file, as is the case under other operating systems, so it does +not remain as a previous version under the original filename.) + +=item -S + +If the C<-S> switch is present I the script name does +not contain a directory, then Perl translates the logical +name DCL$PATH as a searchlist, using each translation as +a directory in which to look for the script. In addition, +if no file type is specified, Perl looks in each directory +for a file matching the name specified, with a blank type, +a type of F<.pl>, and a type of F<.com>, in that order. + +=item -u + +The C<-u> switch causes the VMS debugger to be invoked +after the Perl program is compiled, but before it has +run. It does not create a core dump file. + +=back =head1 Perl functions @@ -248,17 +320,17 @@ As of the time this document was last revised, the following 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, + file tests*, abs, alarm, atan, backticks*, binmode*, bless, caller, chdir, chmod, chown, chomp, chop, chr, close, closedir, cos, crypt*, defined, delete, - die, do, each, endpwent, eof, eval, exec*, exists, - exit, exp, fileno, fork*, getc, getlogin, getpwent*, - getpwnam*, getpwuid*, glob, gmtime*, 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, + die, do, dump*, each, endpwent, eof, eval, exec*, + exists, exit, exp, fileno, fork*, getc, getlogin, + getpwent*, getpwnam*, getpwuid*, glob, gmtime*, 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, print, printf, push, q//, qq//, qw//, - qx//, quotemeta, rand, read, readdir, redo, ref, rename, + qx//*, quotemeta, rand, read, readdir, redo, ref, rename, require, reset, return, reverse, rewinddir, rindex, rmdir, s///, scalar, seek, seekdir, select(internal), select (system call)*, setpwent, shift, sin, sleep, @@ -272,16 +344,27 @@ The following functions were not implemented in the VMS port, and calling them produces a fatal error (usually) or undefined behavior (rarely, we hope): - chroot, dbmclose, dbmopen, dump, fcntl, flock, + chroot, dbmclose, dbmopen, flock, getpgrp, getppid, getpriority, getgrent, getgrgid, getgrnam, setgrent, endgrent, ioctl, link, lstat, msgctl, msgget, msgsend, msgrcv, readlink, semctl, semget, semop, setpgrp, setpriority, shmctl, shmget, - shmread, shmwrite, socketpair, symlink, syscall, truncate + shmread, shmwrite, socketpair, symlink, syscall + +The following functions are available on Perls compiled with Dec C +5.2 or greater and running VMS 7.0 or greater: + + truncate + +The following functions are available on Perls built on VMS 7.2 or +greater: + + fcntl (without locking) The following functions may or may not be implemented, depending on what type of socket support you've built into your copy of Perl: + accept, bind, connect, getpeername, gethostbyname, getnetbyname, getprotobyname, getservbyname, gethostbyaddr, getnetbyaddr, @@ -292,6 +375,7 @@ your copy of Perl: getsockopt, listen, recv, select(system call)*, send, setsockopt, shutdown, socket +=over 4 =item File tests @@ -310,11 +394,39 @@ st_mode field. Finally, C<-d> returns true if passed a device specification without an explicit directory (e.g. C), as well as if passed a directory. +Note: Some sites have reported problems when using the file-access +tests (C<-r>, C<-w>, and C<-x>) on files accessed via DEC's DFS. +Specifically, since DFS does not currently provide access to the +extended file header of files on remote volumes, attempts to +examine the ACL fail, and the file tests will return false, +with C<$!> indicating that the file does not exist. You can +use C on these files, since that checks UIC-based protection +only, and then manually check the appropriate bits, as defined by +your C compiler's F, in the mode value it returns, if you +need an approximation of the file's protections. + +=item backticks + +Backticks create a subprocess, and pass the enclosed string +to it for execution as a DCL command. Since the subprocess is +created directly via C, any valid DCL command string +may be specified. + =item binmode FILEHANDLE -The C 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. +The C operator will attempt to insure that no translation +of carriage control occurs on input from or output to this filehandle. +Since this involves reopening the file and then restoring its +file position indicator, if this function returns FALSE, the +underlying filehandle may no longer point to an open file, or may +point to a different position in the file than before C +was called. + +Note that C is generally not necessary when using normal +filehandles; it is provided so that you can control I/O to existing +record-structured files when necessary. You can also use the +C function in the VMS::Stdio extension to gain finer +control of I/O to files and devices with different record structures. =item crypt PLAINTEXT, USER @@ -343,6 +455,17 @@ C to insure that you'll get the proper value: return 1; } +=item dump + +Rather than causing Perl to abort and dump core, the C +operator invokes the VMS debugger. If you continue to +execute the Perl program under the debugger, control will +be transferred to the label specified as the argument to +C, or, if no label was specified, back to the +beginning of the program. All other state of the program +(I values of variables, open file handles) are not +affected by calling C. + =item exec LIST The C operator behaves in one of two different ways. @@ -358,12 +481,16 @@ handlers to the subprocess are limited.) If the call to C does not follow a call to C, it will cause Perl to exit, and to invoke the command given as an argument to C via C. If the argument -begins with a '$' (other than as part of a filespec), then it +begins with '@' or '$' (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 C's argument to it as parameters. +rest of C's argument to it as parameters. If the token +has no file type, and matches a file with null type, then an +attempt is made to determine whether the file is an executable +image which should be invoked using C or a text file which +should be passed to DCL as a command procedure. You can use C in both ways within the same script, as long as you call C and C in pairs. Perl @@ -382,7 +509,7 @@ process, so there is no opportunity to perform operations in the subprocess before calling C. In general, the use of C and C to create -subprocess is not recommended under VMS; wherever possible, +subprocesses is not recommended under VMS; wherever possible, use the C operator or piped filehandles instead. =item getpwent @@ -412,10 +539,10 @@ true, a warning message is printed, and C is returned. =item kill -In most cases, C kill is implemented via the CRTL's C +In most cases, C is implemented via the CRTL's C function, so it will behave according to that function's documentation. If you send a SIGKILL, however, the $DELPRC system -service is is called directly. This insures that the target +service is called directly. This insures that the target process is actually deleted, if at all possible. (The CRTL's C function is presently implemented via $FORCEX, which is ignored by supervisor-mode images like DCL.) @@ -423,6 +550,10 @@ supervisor-mode images like DCL.) Also, negative signal values don't do anything special under VMS; they're just converted to the corresponding positive value. +=item qx// + +See the entry on C above. + =item select (system call) If Perl was not built with socket support, the system call @@ -447,11 +578,35 @@ though, so caveat scriptor. The C operator creates a subprocess, and passes its arguments to the subprocess for execution as a DCL command. Since the subprocess is created directly via C, any -valid DCL command string may be specified. If LIST consists -of the empty string, C spawns an interactive DCL subprocess, -in the same fashion as typiing B at the DCL prompt. +valid DCL command string may be specified. If the string begins with +'@', it is treated as a DCL command unconditionally. Otherwise, if +the first token contains a character used as a delimiter in file +specification (e.g. C<:> or C<]>), an attempt is made to expand it +using a default type of F<.Exe> and the process defaults, and if +successful, the resulting file is invoked via C. This allows you +to invoke an image directly simply by passing the file specification +to C, a common Unixish idiom. If the token has no file type, +and matches a file with null type, then an attempt is made to +determine whether the file is an executable image which should be +invoked using C or a text file which should be passed to DCL +as a command procedure. + +If LIST consists of the empty string, C spawns an +interactive DCL subprocess, in the same fashion as typing +B at the DCL prompt. + Perl waits for the subprocess to complete before continuing -execution in the current process. +execution in the current process. As described in L, +the return value of C is a fake "status" which follows +POSIX semantics unless the pragma C is in +effect; see the description of C<$?> in this document for more +detail. + +=item time + +The value returned by C