Commit | Line | Data |
---|---|---|
e518068a | 1 | =head1 NAME |
2 | ||
3 | perlvms - VMS-specific documentation for Perl | |
4 | ||
5 | =head1 DESCRIPTION | |
a0d0e21e | 6 | |
748a9306 LW |
7 | Gathered below are notes describing details of Perl 5's |
8 | behavior on VMS. They are a supplement to the regular Perl 5 | |
9 | documentation, so we have focussed on the ways in which Perl | |
10 | 5 functions differently under VMS than it does under Unix, | |
11 | and on the interactions between Perl and the rest of the | |
a0d0e21e | 12 | operating system. We haven't tried to duplicate complete |
748a9306 | 13 | descriptions of Perl features from the main Perl |
a0d0e21e | 14 | documentation, which can be found in the F<[.pod]> |
748a9306 | 15 | subdirectory of the Perl distribution. |
a0d0e21e LW |
16 | |
17 | We hope these notes will save you from confusion and lost | |
748a9306 | 18 | sleep when writing Perl scripts on VMS. If you find we've |
a0d0e21e | 19 | missed something you think should appear here, please don't |
9bc98430 | 20 | hesitate to drop a line to vmsperl@perl.org. |
a0d0e21e | 21 | |
4e592037 | 22 | =head1 Installation |
23 | ||
24 | Directions for building and installing Perl 5 can be found in | |
25 | the file F<README.vms> in the main source directory of the | |
26 | Perl distribution.. | |
27 | ||
e518068a | 28 | =head1 Organization of Perl Images |
748a9306 | 29 | |
e518068a | 30 | =head2 Core Images |
748a9306 LW |
31 | |
32 | During the installation process, three Perl images are produced. | |
33 | F<Miniperl.Exe> is an executable image which contains all of | |
34 | the basic functionality of Perl, but cannot take advantage of | |
35 | Perl extensions. It is used to generate several files needed | |
36 | to build the complete Perl and various extensions. Once you've | |
37 | finished installing Perl, you can delete this image. | |
38 | ||
39 | Most of the complete Perl resides in the shareable image | |
40 | F<PerlShr.Exe>, which provides a core to which the Perl executable | |
41 | image and all Perl extensions are linked. You should place this | |
42 | image in F<Sys$Share>, or define the logical name F<PerlShr> to | |
43 | translate to the full file specification of this image. It should | |
44 | be world readable. (Remember that if a user has execute only access | |
45 | to F<PerlShr>, VMS will treat it as if it were a privileged shareable | |
46 | image, and will therefore require all downstream shareable images to be | |
47 | INSTALLed, etc.) | |
48 | ||
49 | ||
50 | Finally, F<Perl.Exe> is an executable image containing the main | |
51 | entry point for Perl, as well as some initialization code. It | |
52 | should be placed in a public directory, and made world executable. | |
53 | In order to run Perl with command line arguments, you should | |
54 | define a foreign command to invoke this image. | |
55 | ||
56 | =head2 Perl Extensions | |
57 | ||
58 | Perl extensions are packages which provide both XS and Perl code | |
59 | to add new functionality to perl. (XS is a meta-language which | |
60 | simplifies writing C code which interacts with Perl, see | |
2ceaccd7 | 61 | L<perlxs> for more details.) The Perl code for an |
748a9306 LW |
62 | extension is treated like any other library module - it's |
63 | made available in your script through the appropriate | |
64 | C<use> or C<require> statement, and usually defines a Perl | |
65 | package containing the extension. | |
66 | ||
67 | The portion of the extension provided by the XS code may be | |
68 | connected to the rest of Perl in either of two ways. In the | |
69 | B<static> configuration, the object code for the extension is | |
70 | linked directly into F<PerlShr.Exe>, and is initialized whenever | |
71 | Perl is invoked. In the B<dynamic> configuration, the extension's | |
72 | machine code is placed into a separate shareable image, which is | |
73 | mapped by Perl's DynaLoader when the extension is C<use>d or | |
74 | C<require>d in your script. This allows you to maintain the | |
75 | extension as a separate entity, at the cost of keeping track of the | |
76 | additional shareable image. Most extensions can be set up as either | |
77 | static or dynamic. | |
78 | ||
79 | The source code for an extension usually resides in its own | |
80 | directory. At least three files are generally provided: | |
81 | I<Extshortname>F<.xs> (where I<Extshortname> is the portion of | |
82 | the extension's name following the last C<::>), containing | |
83 | the XS code, I<Extshortname>F<.pm>, the Perl library module | |
84 | for the extension, and F<Makefile.PL>, a Perl script which uses | |
85 | the C<MakeMaker> library modules supplied with Perl to generate | |
86 | a F<Descrip.MMS> file for the extension. | |
87 | ||
e518068a | 88 | =head2 Installing static extensions |
748a9306 LW |
89 | |
90 | Since static extensions are incorporated directly into | |
91 | F<PerlShr.Exe>, you'll have to rebuild Perl to incorporate a | |
92 | new extension. You should edit the main F<Descrip.MMS> or F<Makefile> | |
93 | you use to build Perl, adding the extension's name to the C<ext> | |
94 | macro, and the extension's object file to the C<extobj> macro. | |
95 | You'll also need to build the extension's object file, either | |
96 | by adding dependencies to the main F<Descrip.MMS>, or using a | |
97 | separate F<Descrip.MMS> for the extension. Then, rebuild | |
98 | F<PerlShr.Exe> to incorporate the new code. | |
99 | ||
100 | Finally, you'll need to copy the extension's Perl library | |
101 | module to the F<[.>I<Extname>F<]> subdirectory under one | |
102 | of the directories in C<@INC>, where I<Extname> is the name | |
103 | of the extension, with all C<::> replaced by C<.> (e.g. | |
104 | the library module for extension Foo::Bar would be copied | |
105 | to a F<[.Foo.Bar]> subdirectory). | |
106 | ||
e518068a | 107 | =head2 Installing dynamic extensions |
108 | ||
109 | In general, the distributed kit for a Perl extension includes | |
110 | a file named Makefile.PL, which is a Perl program which is used | |
111 | to create a F<Descrip.MMS> file which can be used to build and | |
112 | install the files required by the extension. The kit should be | |
c07a80fd | 113 | unpacked into a directory tree B<not> under the main Perl source |
e518068a | 114 | directory, and the procedure for building the extension is simply |
115 | ||
e518068a | 116 | $ perl Makefile.PL ! Create Descrip.MMS |
117 | $ mmk ! Build necessary files | |
118 | $ mmk test ! Run test code, if supplied | |
119 | $ mmk install ! Install into public Perl tree | |
120 | ||
c07a80fd | 121 | I<N.B.> The procedure by which extensions are built and |
122 | tested creates several levels (at least 4) under the | |
123 | directory in which the extension's source files live. | |
124 | For this reason, you shouldn't nest the source directory | |
39aca757 | 125 | too deeply in your directory structure, lest you exceed RMS' |
c07a80fd | 126 | maximum of 8 levels of subdirectory in a filespec. (You |
127 | can use rooted logical names to get another 8 levels of | |
128 | nesting, if you can't place the files near the top of | |
129 | the physical directory structure.) | |
e518068a | 130 | |
131 | VMS support for this process in the current release of Perl | |
132 | is sufficient to handle most extensions. However, it does | |
133 | not yet recognize extra libraries required to build shareable | |
134 | images which are part of an extension, so these must be added | |
135 | to the linker options file for the extension by hand. For | |
136 | instance, if the F<PGPLOT> extension to Perl requires the | |
137 | F<PGPLOTSHR.EXE> shareable image in order to properly link | |
138 | the Perl extension, then the line C<PGPLOTSHR/Share> must | |
139 | be added to the linker options file F<PGPLOT.Opt> produced | |
140 | during the build process for the Perl extension. | |
141 | ||
142 | By default, the shareable image for an extension is placed | |
bbce6d69 | 143 | F<[.lib.site_perl.auto>I<Arch>.I<Extname>F<]> directory of the |
e518068a | 144 | installed Perl directory tree (where I<Arch> is F<VMS_VAX> or |
bbce6d69 | 145 | F<VMS_AXP>, and I<Extname> is the name of the extension, with |
146 | each C<::> translated to C<.>). (See the MakeMaker documentation | |
147 | for more details on installation options for extensions.) | |
4e592037 | 148 | However, it can be manually placed in any of several locations: |
bbce6d69 | 149 | - the F<[.Lib.Auto.>I<Arch>I<$PVers>I<Extname>F<]> subdirectory |
150 | of one of the directories in C<@INC> (where I<PVers> | |
151 | is the version of Perl you're using, as supplied in C<$]>, | |
152 | with '.' converted to '_'), or | |
748a9306 LW |
153 | - one of the directories in C<@INC>, or |
154 | - a directory which the extensions Perl library module | |
155 | passes to the DynaLoader when asking it to map | |
156 | the shareable image, or | |
157 | - F<Sys$Share> or F<Sys$Library>. | |
158 | If the shareable image isn't in any of these places, you'll need | |
159 | to define a logical name I<Extshortname>, where I<Extshortname> | |
160 | is the portion of the extension's name after the last C<::>, which | |
161 | translates to the full file specification of the shareable image. | |
162 | ||
4e592037 | 163 | =head1 File specifications |
748a9306 | 164 | |
4e592037 | 165 | =head2 Syntax |
a0d0e21e | 166 | |
748a9306 | 167 | We have tried to make Perl aware of both VMS-style and Unix- |
a0d0e21e LW |
168 | style file specifications wherever possible. You may use |
169 | either style, or both, on the command line and in scripts, | |
39aca757 | 170 | but you may not combine the two styles within a single file |
1c9f8daa | 171 | specification. VMS Perl interprets Unix pathnames in much |
172 | the same way as the CRTL (I<e.g.> the first component of | |
173 | an absolute path is read as the device name for the | |
174 | VMS file specification). There are a set of functions | |
175 | provided in the C<VMS::Filespec> package for explicit | |
176 | interconversion between VMS and Unix syntax; its | |
177 | documentation provides more details. | |
178 | ||
179 | Filenames are, of course, still case-insensitive. For | |
180 | consistency, most Perl routines return filespecs using | |
181 | lower case letters only, regardless of the case used in | |
182 | the arguments passed to them. (This is true only when | |
183 | running under VMS; Perl respects the case-sensitivity | |
184 | of OSs like Unix.) | |
a0d0e21e | 185 | |
748a9306 | 186 | We've tried to minimize the dependence of Perl library |
a0d0e21e LW |
187 | modules on Unix syntax, but you may find that some of these, |
188 | as well as some scripts written for Unix systems, will | |
189 | require that you use Unix syntax, since they will assume that | |
4e592037 | 190 | '/' is the directory separator, I<etc.> If you find instances |
748a9306 | 191 | of this in the Perl distribution itself, please let us know, |
a0d0e21e LW |
192 | so we can try to work around them. |
193 | ||
4e592037 | 194 | =head2 Wildcard expansion |
195 | ||
196 | File specifications containing wildcards are allowed both on | |
07698885 | 197 | the command line and within Perl globs (e.g. C<E<lt>*.cE<gt>>). If |
4e592037 | 198 | the wildcard filespec uses VMS syntax, the resultant |
199 | filespecs will follow VMS syntax; if a Unix-style filespec is | |
200 | passed in, Unix-style filespecs will be returned. | |
201 | ||
aa779de1 CB |
202 | In both cases, VMS wildcard expansion is performed. (csh-style |
203 | wildcard expansion is available if you use C<File::Glob::glob>.) | |
4e592037 | 204 | If the wildcard filespec contains a device or directory |
205 | specification, then the resultant filespecs will also contain | |
206 | a device and directory; otherwise, device and directory | |
207 | information are removed. VMS-style resultant filespecs will | |
208 | contain a full device and directory, while Unix-style | |
209 | resultant filespecs will contain only as much of a directory | |
210 | path as was present in the input filespec. For example, if | |
211 | your default directory is Perl_Root:[000000], the expansion | |
212 | of C<[.t]*.*> will yield filespecs like | |
213 | "perl_root:[t]base.dir", while the expansion of C<t/*/*> will | |
214 | yield filespecs like "t/base.dir". (This is done to match | |
215 | the behavior of glob expansion performed by Unix shells.) | |
216 | ||
217 | Similarly, the resultant filespec will contain the file version | |
218 | only if one was present in the input filespec. | |
219 | ||
220 | =head2 Pipes | |
221 | ||
222 | Input and output pipes to Perl filehandles are supported; the | |
223 | "file name" is passed to lib$spawn() for asynchronous | |
224 | execution. You should be careful to close any pipes you have | |
225 | opened in a Perl script, lest you leave any "orphaned" | |
226 | subprocesses around when Perl exits. | |
227 | ||
228 | You may also use backticks to invoke a DCL subprocess, whose | |
229 | output is used as the return value of the expression. The | |
aa779de1 CB |
230 | string between the backticks is handled as if it were the |
231 | argument to the C<system> operator (see below). In this case, | |
232 | Perl will wait for the subprocess to complete before continuing. | |
4e592037 | 233 | |
234 | =head1 PERL5LIB and PERLLIB | |
235 | ||
39aca757 | 236 | The PERL5LIB and PERLLIB logical names work as documented in L<perl>, |
4e592037 | 237 | except that the element separator is '|' instead of ':'. The |
238 | directory specifications may use either VMS or Unix syntax. | |
239 | ||
240 | =head1 Command line | |
241 | ||
242 | =head2 I/O redirection and backgrounding | |
a0d0e21e LW |
243 | |
244 | Perl for VMS supports redirection of input and output on the | |
245 | command line, using a subset of Bourne shell syntax: | |
55497cff | 246 | |
07698885 RGS |
247 | =over |
248 | ||
249 | =item * | |
250 | ||
251 | C<E<lt>file> reads stdin from C<file>, | |
252 | ||
253 | =item * | |
254 | ||
255 | C<E<gt>file> writes stdout to C<file>, | |
256 | ||
257 | =item * | |
258 | ||
259 | C<E<gt>E<gt>file> appends stdout to C<file>, | |
260 | ||
261 | =item * | |
262 | ||
263 | C<2E<gt>file> writes stderr to C<file>, and | |
264 | ||
265 | =item * | |
266 | ||
267 | C<2E<gt>E<gt>file> appends stderr to C<file>. | |
268 | ||
269 | =back | |
a0d0e21e LW |
270 | |
271 | In addition, output may be piped to a subprocess, using the | |
272 | character '|'. Anything after this character on the command | |
273 | line is passed to a subprocess for execution; the subprocess | |
748a9306 | 274 | takes the output of Perl as its input. |
a0d0e21e LW |
275 | |
276 | Finally, if the command line ends with '&', the entire | |
277 | command is run in the background as an asynchronous | |
278 | subprocess. | |
279 | ||
4e592037 | 280 | =head2 Command line switches |
a0d0e21e | 281 | |
4e592037 | 282 | The following command line switches behave differently under |
283 | VMS than described in L<perlrun>. Note also that in order | |
284 | to pass uppercase switches to Perl, you need to enclose | |
285 | them in double-quotes on the command line, since the CRTL | |
286 | downcases all unquoted strings. | |
a0d0e21e | 287 | |
55497cff | 288 | =over 4 |
289 | ||
edc7bc49 CB |
290 | =item -i |
291 | ||
292 | If the C<-i> switch is present but no extension for a backup | |
293 | copy is given, then inplace editing creates a new version of | |
294 | a file; the existing copy is not deleted. (Note that if | |
295 | an extension is given, an existing file is renamed to the backup | |
296 | file, as is the case under other operating systems, so it does | |
297 | not remain as a previous version under the original filename.) | |
298 | ||
4e592037 | 299 | =item -S |
a0d0e21e | 300 | |
4e592037 | 301 | If the C<-S> switch is present I<and> the script name does |
302 | not contain a directory, then Perl translates the logical | |
303 | name DCL$PATH as a searchlist, using each translation as | |
304 | a directory in which to look for the script. In addition, | |
305 | if no file type is specified, Perl looks in each directory | |
306 | for a file matching the name specified, with a blank type, | |
307 | a type of F<.pl>, and a type of F<.com>, in that order. | |
a0d0e21e | 308 | |
4e592037 | 309 | =item -u |
748a9306 | 310 | |
4e592037 | 311 | The C<-u> switch causes the VMS debugger to be invoked |
312 | after the Perl program is compiled, but before it has | |
313 | run. It does not create a core dump file. | |
748a9306 | 314 | |
55497cff | 315 | =back |
316 | ||
748a9306 | 317 | =head1 Perl functions |
a0d0e21e LW |
318 | |
319 | As of the time this document was last revised, the following | |
748a9306 | 320 | Perl functions were implemented in the VMS port of Perl |
a0d0e21e LW |
321 | (functions marked with * are discussed in more detail below): |
322 | ||
4fdae800 | 323 | file tests*, abs, alarm, atan, backticks*, binmode*, bless, |
a0d0e21e | 324 | caller, chdir, chmod, chown, chomp, chop, chr, |
c07a80fd | 325 | close, closedir, cos, crypt*, defined, delete, |
4e592037 | 326 | die, do, dump*, each, endpwent, eof, eval, exec*, |
327 | exists, exit, exp, fileno, fork*, getc, getlogin, | |
328 | getpwent*, getpwnam*, getpwuid*, glob, gmtime*, goto, | |
329 | grep, hex, import, index, int, join, keys, kill*, | |
330 | last, lc, lcfirst, length, local, localtime, log, m//, | |
331 | map, mkdir, my, next, no, oct, open, opendir, ord, pack, | |
c07a80fd | 332 | pipe, pop, pos, print, printf, push, q//, qq//, qw//, |
4fdae800 | 333 | qx//*, quotemeta, rand, read, readdir, redo, ref, rename, |
a0d0e21e | 334 | require, reset, return, reverse, rewinddir, rindex, |
e518068a | 335 | rmdir, s///, scalar, seek, seekdir, select(internal), |
336 | select (system call)*, setpwent, shift, sin, sleep, | |
337 | sort, splice, split, sprintf, sqrt, srand, stat, | |
338 | study, substr, sysread, system*, syswrite, tell, | |
339 | telldir, tie, time, times*, tr///, uc, ucfirst, umask, | |
340 | undef, unlink*, unpack, untie, unshift, use, utime*, | |
341 | values, vec, wait, waitpid*, wantarray, warn, write, y/// | |
a0d0e21e LW |
342 | |
343 | The following functions were not implemented in the VMS port, | |
344 | and calling them produces a fatal error (usually) or | |
345 | undefined behavior (rarely, we hope): | |
346 | ||
35b2760a | 347 | chroot, dbmclose, dbmopen, flock, |
c07a80fd | 348 | getpgrp, getppid, getpriority, getgrent, getgrgid, |
349 | getgrnam, setgrent, endgrent, ioctl, link, lstat, | |
350 | msgctl, msgget, msgsend, msgrcv, readlink, semctl, | |
351 | semget, semop, setpgrp, setpriority, shmctl, shmget, | |
bf99883d HM |
352 | shmread, shmwrite, socketpair, symlink, syscall |
353 | ||
35b2760a CB |
354 | The following functions are available on Perls compiled with Dec C |
355 | 5.2 or greater and running VMS 7.0 or greater: | |
bf99883d HM |
356 | |
357 | truncate | |
a0d0e21e | 358 | |
35b2760a CB |
359 | The following functions are available on Perls built on VMS 7.2 or |
360 | greater: | |
361 | ||
362 | fcntl (without locking) | |
363 | ||
a0d0e21e LW |
364 | The following functions may or may not be implemented, |
365 | depending on what type of socket support you've built into | |
748a9306 | 366 | your copy of Perl: |
4e592037 | 367 | |
a0d0e21e LW |
368 | accept, bind, connect, getpeername, |
369 | gethostbyname, getnetbyname, getprotobyname, | |
370 | getservbyname, gethostbyaddr, getnetbyaddr, | |
371 | getprotobynumber, getservbyport, gethostent, | |
372 | getnetent, getprotoent, getservent, sethostent, | |
373 | setnetent, setprotoent, setservent, endhostent, | |
374 | endnetent, endprotoent, endservent, getsockname, | |
c07a80fd | 375 | getsockopt, listen, recv, select(system call)*, |
376 | send, setsockopt, shutdown, socket | |
a0d0e21e | 377 | |
55497cff | 378 | =over 4 |
a0d0e21e LW |
379 | |
380 | =item File tests | |
381 | ||
748a9306 LW |
382 | The tests C<-b>, C<-B>, C<-c>, C<-C>, C<-d>, C<-e>, C<-f>, |
383 | C<-o>, C<-M>, C<-s>, C<-S>, C<-t>, C<-T>, and C<-z> work as | |
384 | advertised. The return values for C<-r>, C<-w>, and C<-x> | |
385 | tell you whether you can actually access the file; this may | |
386 | not reflect the UIC-based file protections. Since real and | |
387 | effective UIC don't differ under VMS, C<-O>, C<-R>, C<-W>, | |
388 | and C<-X> are equivalent to C<-o>, C<-r>, C<-w>, and C<-x>. | |
389 | Similarly, several other tests, including C<-A>, C<-g>, C<-k>, | |
390 | C<-l>, C<-p>, and C<-u>, aren't particularly meaningful under | |
391 | VMS, and the values returned by these tests reflect whatever | |
392 | your CRTL C<stat()> routine does to the equivalent bits in the | |
393 | st_mode field. Finally, C<-d> returns true if passed a device | |
394 | specification without an explicit directory (e.g. C<DUA1:>), as | |
395 | well as if passed a directory. | |
396 | ||
4e592037 | 397 | Note: Some sites have reported problems when using the file-access |
398 | tests (C<-r>, C<-w>, and C<-x>) on files accessed via DEC's DFS. | |
399 | Specifically, since DFS does not currently provide access to the | |
400 | extended file header of files on remote volumes, attempts to | |
401 | examine the ACL fail, and the file tests will return false, | |
402 | with C<$!> indicating that the file does not exist. You can | |
403 | use C<stat> on these files, since that checks UIC-based protection | |
404 | only, and then manually check the appropriate bits, as defined by | |
405 | your C compiler's F<stat.h>, in the mode value it returns, if you | |
406 | need an approximation of the file's protections. | |
407 | ||
4fdae800 | 408 | =item backticks |
409 | ||
410 | Backticks create a subprocess, and pass the enclosed string | |
411 | to it for execution as a DCL command. Since the subprocess is | |
412 | created directly via C<lib$spawn()>, any valid DCL command string | |
413 | may be specified. | |
414 | ||
748a9306 LW |
415 | =item binmode FILEHANDLE |
416 | ||
1c9f8daa | 417 | The C<binmode> operator will attempt to insure that no translation |
418 | of carriage control occurs on input from or output to this filehandle. | |
419 | Since this involves reopening the file and then restoring its | |
420 | file position indicator, if this function returns FALSE, the | |
421 | underlying filehandle may no longer point to an open file, or may | |
422 | point to a different position in the file than before C<binmode> | |
423 | was called. | |
424 | ||
425 | Note that C<binmode> is generally not necessary when using normal | |
426 | filehandles; it is provided so that you can control I/O to existing | |
427 | record-structured files when necessary. You can also use the | |
428 | C<vmsfopen> function in the VMS::Stdio extension to gain finer | |
429 | control of I/O to files and devices with different record structures. | |
a0d0e21e | 430 | |
c07a80fd | 431 | =item crypt PLAINTEXT, USER |
432 | ||
433 | The C<crypt> operator uses the C<sys$hash_password> system | |
434 | service to generate the hashed representation of PLAINTEXT. | |
435 | If USER is a valid username, the algorithm and salt values | |
436 | are taken from that user's UAF record. If it is not, then | |
437 | the preferred algorithm and a salt of 0 are used. The | |
438 | quadword encrypted value is returned as an 8-character string. | |
439 | ||
440 | The value returned by C<crypt> may be compared against | |
441 | the encrypted password from the UAF returned by the C<getpw*> | |
442 | functions, in order to authenticate users. If you're | |
443 | going to do this, remember that the encrypted password in | |
444 | the UAF was generated using uppercase username and | |
445 | password strings; you'll have to upcase the arguments to | |
446 | C<crypt> to insure that you'll get the proper value: | |
447 | ||
448 | sub validate_passwd { | |
449 | my($user,$passwd) = @_; | |
450 | my($pwdhash); | |
451 | if ( !($pwdhash = (getpwnam($user))[1]) || | |
452 | $pwdhash ne crypt("\U$passwd","\U$name") ) { | |
453 | intruder_alert($name); | |
454 | } | |
455 | return 1; | |
456 | } | |
457 | ||
4e592037 | 458 | =item dump |
459 | ||
460 | Rather than causing Perl to abort and dump core, the C<dump> | |
461 | operator invokes the VMS debugger. If you continue to | |
462 | execute the Perl program under the debugger, control will | |
463 | be transferred to the label specified as the argument to | |
464 | C<dump>, or, if no label was specified, back to the | |
465 | beginning of the program. All other state of the program | |
466 | (I<e.g.> values of variables, open file handles) are not | |
467 | affected by calling C<dump>. | |
468 | ||
748a9306 | 469 | =item exec LIST |
a0d0e21e | 470 | |
748a9306 LW |
471 | The C<exec> operator behaves in one of two different ways. |
472 | If called after a call to C<fork>, it will invoke the CRTL | |
473 | C<execv()> routine, passing its arguments to the subprocess | |
474 | created by C<fork> for execution. In this case, it is | |
475 | subject to all limitations that affect C<execv()>. (In | |
a0d0e21e LW |
476 | particular, this usually means that the command executed in |
477 | the subprocess must be an image compiled from C source code, | |
478 | and that your options for passing file descriptors and signal | |
479 | handlers to the subprocess are limited.) | |
480 | ||
748a9306 LW |
481 | If the call to C<exec> does not follow a call to C<fork>, it |
482 | will cause Perl to exit, and to invoke the command given as | |
483 | an argument to C<exec> via C<lib$do_command>. If the argument | |
aa779de1 | 484 | begins with '@' or '$' (other than as part of a filespec), then it |
a0d0e21e LW |
485 | is executed as a DCL command. Otherwise, the first token on |
486 | the command line is treated as the filespec of an image to | |
487 | run, and an attempt is made to invoke it (using F<.Exe> and | |
488 | the process defaults to expand the filespec) and pass the | |
c93fa817 GS |
489 | rest of C<exec>'s argument to it as parameters. If the token |
490 | has no file type, and matches a file with null type, then an | |
491 | attempt is made to determine whether the file is an executable | |
492 | image which should be invoked using C<MCR> or a text file which | |
493 | should be passed to DCL as a command procedure. | |
a0d0e21e | 494 | |
748a9306 LW |
495 | You can use C<exec> in both ways within the same script, as |
496 | long as you call C<fork> and C<exec> in pairs. Perl | |
497 | keeps track of how many times C<fork> and C<exec> have been | |
498 | called, and will call the CRTL C<execv()> routine if there have | |
499 | previously been more calls to C<fork> than to C<exec>. | |
a0d0e21e LW |
500 | |
501 | =item fork | |
502 | ||
748a9306 LW |
503 | The C<fork> operator works in the same way as the CRTL |
504 | C<vfork()> routine, which is quite different under VMS than | |
505 | under Unix. Specifically, while C<fork> returns 0 after it | |
506 | is called and the subprocess PID after C<exec> is called, in | |
a0d0e21e LW |
507 | both cases the thread of execution is within the parent |
508 | process, so there is no opportunity to perform operations in | |
748a9306 | 509 | the subprocess before calling C<exec>. |
a0d0e21e | 510 | |
748a9306 | 511 | In general, the use of C<fork> and C<exec> to create |
9bc98430 | 512 | subprocesses is not recommended under VMS; wherever possible, |
748a9306 LW |
513 | use the C<system> operator or piped filehandles instead. |
514 | ||
515 | =item getpwent | |
c07a80fd | 516 | |
748a9306 | 517 | =item getpwnam |
c07a80fd | 518 | |
748a9306 LW |
519 | =item getpwuid |
520 | ||
521 | These operators obtain the information described in L<perlfunc>, | |
522 | if you have the privileges necessary to retrieve the named user's | |
523 | UAF information via C<sys$getuai>. If not, then only the C<$name>, | |
524 | C<$uid>, and C<$gid> items are returned. The C<$dir> item contains | |
525 | the login directory in VMS syntax, while the C<$comment> item | |
526 | contains the login directory in Unix syntax. The C<$gcos> item | |
527 | contains the owner field from the UAF record. The C<$quota> | |
528 | item is not used. | |
a0d0e21e | 529 | |
e518068a | 530 | =item gmtime |
531 | ||
532 | The C<gmtime> operator will function properly if you have a | |
533 | working CRTL C<gmtime()> routine, or if the logical name | |
534 | SYS$TIMEZONE_DIFFERENTIAL is defined as the number of seconds | |
535 | which must be added to UTC to yield local time. (This logical | |
536 | name is defined automatically if you are running a version of | |
537 | VMS with built-in UTC support.) If neither of these cases is | |
538 | true, a warning message is printed, and C<undef> is returned. | |
539 | ||
540 | =item kill | |
541 | ||
39aca757 | 542 | In most cases, C<kill> is implemented via the CRTL's C<kill()> |
e518068a | 543 | function, so it will behave according to that function's |
544 | documentation. If you send a SIGKILL, however, the $DELPRC system | |
10a676f8 | 545 | service is called directly. This insures that the target |
e518068a | 546 | process is actually deleted, if at all possible. (The CRTL's C<kill()> |
547 | function is presently implemented via $FORCEX, which is ignored by | |
548 | supervisor-mode images like DCL.) | |
549 | ||
550 | Also, negative signal values don't do anything special under | |
551 | VMS; they're just converted to the corresponding positive value. | |
552 | ||
4fdae800 | 553 | =item qx// |
554 | ||
555 | See the entry on C<backticks> above. | |
556 | ||
e518068a | 557 | =item select (system call) |
558 | ||
559 | If Perl was not built with socket support, the system call | |
560 | version of C<select> is not available at all. If socket | |
561 | support is present, then the system call version of | |
562 | C<select> functions only for file descriptors attached | |
563 | to sockets. It will not provide information about regular | |
564 | files or pipes, since the CRTL C<select()> routine does not | |
565 | provide this functionality. | |
566 | ||
748a9306 | 567 | =item stat EXPR |
a0d0e21e | 568 | |
748a9306 LW |
569 | Since VMS keeps track of files according to a different scheme |
570 | than Unix, it's not really possible to represent the file's ID | |
571 | in the C<st_dev> and C<st_ino> fields of a C<struct stat>. Perl | |
572 | tries its best, though, and the values it uses are pretty unlikely | |
573 | to be the same for two different files. We can't guarantee this, | |
574 | though, so caveat scriptor. | |
575 | ||
576 | =item system LIST | |
577 | ||
578 | The C<system> operator creates a subprocess, and passes its | |
a0d0e21e | 579 | arguments to the subprocess for execution as a DCL command. |
e518068a | 580 | Since the subprocess is created directly via C<lib$spawn()>, any |
aa779de1 CB |
581 | valid DCL command string may be specified. If the string begins with |
582 | '@', it is treated as a DCL command unconditionally. Otherwise, if | |
583 | the first token contains a character used as a delimiter in file | |
584 | specification (e.g. C<:> or C<]>), an attempt is made to expand it | |
585 | using a default type of F<.Exe> and the process defaults, and if | |
586 | successful, the resulting file is invoked via C<MCR>. This allows you | |
587 | to invoke an image directly simply by passing the file specification | |
c93fa817 GS |
588 | to C<system>, a common Unixish idiom. If the token has no file type, |
589 | and matches a file with null type, then an attempt is made to | |
590 | determine whether the file is an executable image which should be | |
591 | invoked using C<MCR> or a text file which should be passed to DCL | |
592 | as a command procedure. | |
593 | ||
594 | If LIST consists of the empty string, C<system> spawns an | |
a2293a43 | 595 | interactive DCL subprocess, in the same fashion as typing |
c93fa817 GS |
596 | B<SPAWN> at the DCL prompt. |
597 | ||
748a9306 | 598 | Perl waits for the subprocess to complete before continuing |
4fdae800 | 599 | execution in the current process. As described in L<perlfunc>, |
600 | the return value of C<system> is a fake "status" which follows | |
c6966fea | 601 | POSIX semantics unless the pragma C<use vmsish 'status'> is in |
1b0c4952 CB |
602 | effect; see the description of C<$?> in this document for more |
603 | detail. | |
a0d0e21e | 604 | |
1c9f8daa | 605 | =item time |
606 | ||
607 | The value returned by C<time> is the offset in seconds from | |
608 | 01-JAN-1970 00:00:00 (just like the CRTL's times() routine), in order | |
609 | to make life easier for code coming in from the POSIX/Unix world. | |
610 | ||
a0d0e21e LW |
611 | =item times |
612 | ||
748a9306 LW |
613 | The array returned by the C<times> operator is divided up |
614 | according to the same rules the CRTL C<times()> routine. | |
a0d0e21e LW |
615 | Therefore, the "system time" elements will always be 0, since |
616 | there is no difference between "user time" and "system" time | |
39aca757 | 617 | under VMS, and the time accumulated by a subprocess may or may |
a0d0e21e | 618 | not appear separately in the "child time" field, depending on |
748a9306 LW |
619 | whether L<times> keeps track of subprocesses separately. Note |
620 | especially that the VAXCRTL (at least) keeps track only of | |
621 | subprocesses spawned using L<fork> and L<exec>; it will not | |
a2293a43 | 622 | accumulate the times of subprocesses spawned via pipes, L<system>, |
748a9306 LW |
623 | or backticks. |
624 | ||
16d20bd9 AD |
625 | =item unlink LIST |
626 | ||
627 | C<unlink> will delete the highest version of a file only; in | |
628 | order to delete all versions, you need to say | |
39aca757 | 629 | |
35b2760a | 630 | 1 while unlink LIST; |
39aca757 | 631 | |
16d20bd9 AD |
632 | You may need to make this change to scripts written for a |
633 | Unix system which expect that after a call to C<unlink>, | |
634 | no files with the names passed to C<unlink> will exist. | |
4633a7c4 LW |
635 | (Note: This can be changed at compile time; if you |
636 | C<use Config> and C<$Config{'d_unlink_all_versions'}> is | |
637 | C<define>, then C<unlink> will delete all versions of a | |
638 | file on the first call.) | |
16d20bd9 AD |
639 | |
640 | C<unlink> will delete a file if at all possible, even if it | |
641 | requires changing file protection (though it won't try to | |
642 | change the protection of the parent directory). You can tell | |
643 | whether you've got explicit delete access to a file by using the | |
644 | C<VMS::Filespec::candelete> operator. For instance, in order | |
645 | to delete only files to which you have delete access, you could | |
646 | say something like | |
4e592037 | 647 | |
16d20bd9 AD |
648 | sub safe_unlink { |
649 | my($file,$num); | |
650 | foreach $file (@_) { | |
651 | next unless VMS::Filespec::candelete($file); | |
652 | $num += unlink $file; | |
653 | } | |
654 | $num; | |
655 | } | |
4e592037 | 656 | |
657 | (or you could just use C<VMS::Stdio::remove>, if you've installed | |
658 | the VMS::Stdio extension distributed with Perl). If C<unlink> has to | |
659 | change the file protection to delete the file, and you interrupt it | |
660 | in midstream, the file may be left intact, but with a changed ACL | |
661 | allowing you delete access. | |
16d20bd9 | 662 | |
748a9306 LW |
663 | =item utime LIST |
664 | ||
665 | Since ODS-2, the VMS file structure for disk files, does not keep | |
666 | track of access times, this operator changes only the modification | |
667 | time of the file (VMS revision date). | |
668 | ||
669 | =item waitpid PID,FLAGS | |
670 | ||
39aca757 JH |
671 | If PID is a subprocess started by a piped C<open()> (see L<open>), |
672 | C<waitpid> will wait for that subprocess, and return its final | |
35b2760a CB |
673 | status value in C<$?>. If PID is a subprocess created in some other |
674 | way (e.g. SPAWNed before Perl was invoked), or is not a subprocess | |
675 | of the current process, C<waitpid> will attempt to read from the | |
676 | process's termination mailbox, making the final status available in | |
677 | C<$?> when the process completes. If the process specified by PID | |
678 | has no termination mailbox, C<waitpid> will simply check once per | |
679 | second whether the process has completed, and return when it has. | |
680 | (If PID specifies a process that isn't a subprocess of the current | |
681 | process, and you invoked Perl with the C<-w> switch, a warning will | |
682 | be issued.) | |
683 | ||
684 | Returns PID on success, -1 on error. The FLAGS argument is ignored | |
685 | in all cases. | |
a0d0e21e | 686 | |
55497cff | 687 | =back |
688 | ||
a5f75d66 AD |
689 | =head1 Perl variables |
690 | ||
55497cff | 691 | The following VMS-specific information applies to the indicated |
692 | "special" Perl variables, in addition to the general information | |
a2293a43 | 693 | in L<perlvar>. Where there is a conflict, this information |
55497cff | 694 | takes precedence. |
695 | ||
696 | =over 4 | |
697 | ||
a5f75d66 AD |
698 | =item %ENV |
699 | ||
f675dbe5 CB |
700 | The operation of the C<%ENV> array depends on the translation |
701 | of the logical name F<PERL_ENV_TABLES>. If defined, it should | |
702 | be a search list, each element of which specifies a location | |
703 | for C<%ENV> elements. If you tell Perl to read or set the | |
704 | element C<$ENV{>I<name>C<}>, then Perl uses the translations of | |
705 | F<PERL_ENV_TABLES> as follows: | |
706 | ||
707 | =over 4 | |
708 | ||
709 | =item CRTL_ENV | |
710 | ||
711 | This string tells Perl to consult the CRTL's internal C<environ> | |
712 | array of key-value pairs, using I<name> as the key. In most cases, | |
713 | this contains only a few keys, but if Perl was invoked via the C | |
714 | C<exec[lv]e()> function, as is the case for CGI processing by some | |
715 | HTTP servers, then the C<environ> array may have been populated by | |
716 | the calling program. | |
717 | ||
718 | =item CLISYM_[LOCAL] | |
719 | ||
720 | A string beginning with C<CLISYM_>tells Perl to consult the CLI's | |
721 | symbol tables, using I<name> as the name of the symbol. When reading | |
722 | an element of C<%ENV>, the local symbol table is scanned first, followed | |
723 | by the global symbol table.. The characters following C<CLISYM_> are | |
724 | significant when an element of C<%ENV> is set or deleted: if the | |
725 | complete string is C<CLISYM_LOCAL>, the change is made in the local | |
39aca757 | 726 | symbol table; otherwise the global symbol table is changed. |
f675dbe5 CB |
727 | |
728 | =item Any other string | |
729 | ||
730 | If an element of F<PERL_ENV_TABLES> translates to any other string, | |
731 | that string is used as the name of a logical name table, which is | |
732 | consulted using I<name> as the logical name. The normal search | |
733 | order of access modes is used. | |
734 | ||
735 | =back | |
736 | ||
737 | F<PERL_ENV_TABLES> is translated once when Perl starts up; any changes | |
738 | you make while Perl is running do not affect the behavior of C<%ENV>. | |
739 | If F<PERL_ENV_TABLES> is not defined, then Perl defaults to consulting | |
740 | first the logical name tables specified by F<LNM$FILE_DEV>, and then | |
741 | the CRTL C<environ> array. | |
742 | ||
743 | In all operations on %ENV, the key string is treated as if it | |
744 | were entirely uppercase, regardless of the case actually | |
745 | specified in the Perl expression. | |
746 | ||
747 | When an element of C<%ENV> is read, the locations to which | |
748 | F<PERL_ENV_TABLES> points are checked in order, and the value | |
749 | obtained from the first successful lookup is returned. If the | |
750 | name of the C<%ENV> element contains a semi-colon, it and | |
751 | any characters after it are removed. These are ignored when | |
752 | the CRTL C<environ> array or a CLI symbol table is consulted. | |
753 | However, the name is looked up in a logical name table, the | |
754 | suffix after the semi-colon is treated as the translation index | |
755 | to be used for the lookup. This lets you look up successive values | |
756 | for search list logical names. For instance, if you say | |
a5f75d66 AD |
757 | |
758 | $ Define STORY once,upon,a,time,there,was | |
759 | $ perl -e "for ($i = 0; $i <= 6; $i++) " - | |
740ce14c | 760 | _$ -e "{ print $ENV{'story;'.$i},' '}" |
a5f75d66 | 761 | |
f675dbe5 CB |
762 | Perl will print C<ONCE UPON A TIME THERE WAS>, assuming, of course, |
763 | that F<PERL_ENV_TABLES> is set up so that the logical name C<story> | |
764 | is found, rather than a CLI symbol or CRTL C<environ> element with | |
765 | the same name. | |
766 | ||
3eeba6fb | 767 | When an element of C<%ENV> is set to a defined string, the |
f675dbe5 CB |
768 | corresponding definition is made in the location to which the |
769 | first translation of F<PERL_ENV_TABLES> points. If this causes a | |
770 | logical name to be created, it is defined in supervisor mode. | |
3eeba6fb CB |
771 | (The same is done if an existing logical name was defined in |
772 | executive or kernel mode; an existing user or supervisor mode | |
773 | logical name is reset to the new value.) If the value is an empty | |
774 | string, the logical name's translation is defined as a single NUL | |
775 | (ASCII 00) character, since a logical name cannot translate to a | |
776 | zero-length string. (This restriction does not apply to CLI symbols | |
777 | or CRTL C<environ> values; they are set to the empty string.) | |
f675dbe5 CB |
778 | An element of the CRTL C<environ> array can be set only if your |
779 | copy of Perl knows about the CRTL's C<setenv()> function. (This is | |
780 | present only in some versions of the DECCRTL; check C<$Config{d_setenv}> | |
781 | to see whether your copy of Perl was built with a CRTL that has this | |
782 | function.) | |
39aca757 | 783 | |
3eeba6fb | 784 | When an element of C<%ENV> is set to C<undef>, |
f675dbe5 CB |
785 | the element is looked up as if it were being read, and if it is |
786 | found, it is deleted. (An item "deleted" from the CRTL C<environ> | |
787 | array is set to the empty string; this can only be done if your | |
788 | copy of Perl knows about the CRTL C<setenv()> function.) Using | |
789 | C<delete> to remove an element from C<%ENV> has a similar effect, | |
790 | but after the element is deleted, another attempt is made to | |
791 | look up the element, so an inner-mode logical name or a name in | |
792 | another location will replace the logical name just deleted. | |
3eeba6fb CB |
793 | In either case, only the first value found searching PERL_ENV_TABLES |
794 | is altered. It is not possible at present to define a search list | |
795 | logical name via %ENV. | |
f675dbe5 CB |
796 | |
797 | The element C<$ENV{DEFAULT}> is special: when read, it returns | |
798 | Perl's current default device and directory, and when set, it | |
799 | resets them, regardless of the definition of F<PERL_ENV_TABLES>. | |
800 | It cannot be cleared or deleted; attempts to do so are silently | |
801 | ignored. | |
b7b1864f CB |
802 | |
803 | Note that if you want to pass on any elements of the | |
804 | C-local environ array to a subprocess which isn't | |
805 | started by fork/exec, or isn't running a C program, you | |
806 | can "promote" them to logical names in the current | |
807 | process, which will then be inherited by all subprocesses, | |
808 | by saying | |
809 | ||
810 | foreach my $key (qw[C-local keys you want promoted]) { | |
811 | my $temp = $ENV{$key}; # read from C-local array | |
812 | $ENV{$key} = $temp; # and define as logical name | |
813 | } | |
814 | ||
815 | (You can't just say C<$ENV{$key} = $ENV{$key}>, since the | |
816 | Perl optimizer is smart enough to elide the expression.) | |
a5f75d66 | 817 | |
6be8f7a6 JH |
818 | Don't try to clear C<%ENV> by saying C<%ENV = ();>, it will throw |
819 | a fatal error. This is equivalent to doing the following from DCL: | |
820 | ||
821 | DELETE/LOGICAL * | |
822 | ||
823 | You can imagine how bad things would be if, for example, the SYS$MANAGER | |
824 | or SYS$SYSTEM logicals were deleted. | |
4a0d0822 | 825 | |
740ce14c | 826 | At present, the first time you iterate over %ENV using |
edc7bc49 CB |
827 | C<keys>, or C<values>, you will incur a time penalty as all |
828 | logical names are read, in order to fully populate %ENV. | |
829 | Subsequent iterations will not reread logical names, so they | |
830 | won't be as slow, but they also won't reflect any changes | |
f675dbe5 CB |
831 | to logical name tables caused by other programs. |
832 | ||
833 | You do need to be careful with the logicals representing process-permanent | |
834 | files, such as C<SYS$INPUT> and C<SYS$OUTPUT>. The translations for these | |
835 | logicals are prepended with a two-byte binary value (0x1B 0x00) that needs to be | |
39aca757 | 836 | stripped off if you want to use it. (In previous versions of Perl it wasn't |
f675dbe5 CB |
837 | possible to get the values of these logicals, as the null byte acted as an |
838 | end-of-string marker) | |
a5f75d66 | 839 | |
a5f75d66 AD |
840 | =item $! |
841 | ||
842 | The string value of C<$!> is that returned by the CRTL's | |
843 | strerror() function, so it will include the VMS message for | |
844 | VMS-specific errors. The numeric value of C<$!> is the | |
845 | value of C<errno>, except if errno is EVMSERR, in which | |
846 | case C<$!> contains the value of vaxc$errno. Setting C<$!> | |
4e592037 | 847 | always sets errno to the value specified. If this value is |
848 | EVMSERR, it also sets vaxc$errno to 4 (NONAME-F-NOMSG), so | |
849 | that the string value of C<$!> won't reflect the VMS error | |
850 | message from before C<$!> was set. | |
851 | ||
852 | =item $^E | |
853 | ||
854 | This variable provides direct access to VMS status values | |
855 | in vaxc$errno, which are often more specific than the | |
856 | generic Unix-style error messages in C<$!>. Its numeric value | |
857 | is the value of vaxc$errno, and its string value is the | |
858 | corresponding VMS message string, as retrieved by sys$getmsg(). | |
859 | Setting C<$^E> sets vaxc$errno to the value specified. | |
860 | ||
4fdae800 | 861 | =item $? |
862 | ||
863 | The "status value" returned in C<$?> is synthesized from the | |
864 | actual exit status of the subprocess in a way that approximates | |
865 | POSIX wait(5) semantics, in order to allow Perl programs to | |
866 | portably test for successful completion of subprocesses. The | |
867 | low order 8 bits of C<$?> are always 0 under VMS, since the | |
868 | termination status of a process may or may not have been | |
869 | generated by an exception. The next 8 bits are derived from | |
39aca757 | 870 | the severity portion of the subprocess' exit status: if the |
4fdae800 | 871 | severity was success or informational, these bits are all 0; |
9bc98430 CB |
872 | if the severity was warning, they contain a value of 1; if the |
873 | severity was error or fatal error, they contain the actual | |
874 | severity bits, which turns out to be a value of 2 for error | |
875 | and 4 for fatal error. | |
876 | ||
4fdae800 | 877 | As a result, C<$?> will always be zero if the subprocess' exit |
878 | status indicated successful completion, and non-zero if a | |
9bc98430 CB |
879 | warning or error occurred. Conversely, when setting C<$?> in |
880 | an END block, an attempt is made to convert the POSIX value | |
881 | into a native status intelligible to the operating system upon | |
882 | exiting Perl. What this boils down to is that setting C<$?> | |
883 | to zero results in the generic success value SS$_NORMAL, and | |
884 | setting C<$?> to a non-zero value results in the generic | |
885 | failure status SS$_ABORT. See also L<perlport/exit>. | |
4fdae800 | 886 | |
1b0c4952 | 887 | The pragma C<use vmsish 'status'> makes C<$?> reflect the actual |
9bc98430 CB |
888 | VMS exit status instead of the default emulation of POSIX status |
889 | described above. This pragma also disables the conversion of | |
890 | non-zero values to SS$_ABORT when setting C<$?> in an END | |
891 | block (but zero will still be converted to SS$_NORMAL). | |
4fdae800 | 892 | |
4e592037 | 893 | =item $| |
894 | ||
895 | Setting C<$|> for an I/O stream causes data to be flushed | |
896 | all the way to disk on each write (I<i.e.> not just to | |
897 | the underlying RMS buffers for a file). In other words, | |
898 | it's equivalent to calling fflush() and fsync() from C. | |
a5f75d66 | 899 | |
55497cff | 900 | =back |
901 | ||
bf99883d HM |
902 | =head1 Standard modules with VMS-specific differences |
903 | ||
904 | =head2 SDBM_File | |
905 | ||
270c2ced | 906 | SDBM_File works properly on VMS. It has, however, one minor |
4a4eefd0 GS |
907 | difference. The database directory file created has a F<.sdbm_dir> |
908 | extension rather than a F<.dir> extension. F<.dir> files are VMS filesystem | |
bf99883d HM |
909 | directory files, and using them for other purposes could cause unacceptable |
910 | problems. | |
911 | ||
748a9306 | 912 | =head1 Revision date |
a0d0e21e | 913 | |
35b2760a | 914 | This document was last updated on 2-Oct-2001, for Perl 5, |
9bc98430 | 915 | patchlevel 8. |
e518068a | 916 | |
917 | =head1 AUTHOR | |
918 | ||
aa779de1 | 919 | Charles Bailey <bailey@cor.newman.upenn.edu> |
9bc98430 | 920 | Craig Berry <craigberry@mac.com> |
aa779de1 | 921 | Dan Sugalski <dan@sidhe.org> |