X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlport.pod;h=3b11a4f45eeebe8403908636098ee4db99a0e852;hb=ba370e9b8a212c313d985163053c7ed938fcae22;hp=6837b4c54909296a49f4063ff4b226431a8c2e4f;hpb=87275199ef473a0bd08ce6f46db30d4d432f4876;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlport.pod b/pod/perlport.pod index 6837b4c..3b11a4f 100644 --- a/pod/perlport.pod +++ b/pod/perlport.pod @@ -75,7 +75,7 @@ This information should not be considered complete; it includes possibly transient information about idiosyncrasies of some of the ports, almost all of which are in a state of constant evolution. Thus, this material should be considered a perpetual work in progress -(EIMG SRC="yellow_sign.gif" ALT="Under Construction"E). +(Under Construction). =head1 ISSUES @@ -90,10 +90,30 @@ Perl uses C<\n> to represent the "logical" newline, where what is logical may depend on the platform in use. In MacPerl, C<\n> always means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but when accessing a file in "text" mode, STDIO translates it to (or -from) C<\015\012>, depending on whether your reading or writing. +from) C<\015\012>, depending on whether you're reading or writing. Unix does the same thing on ttys in canonical mode. C<\015\012> is commonly referred to as CRLF. +A common cause of unportable programs is the misuse of chop() to trim +newlines: + + # XXX UNPORTABLE! + while() { + chop; + @array = split(/:/); + #... + } + +You can get away with this on Unix and MacOS (they have a single +character end-of-line), but the same program will break under DOSish +perls because you're only chop()ing half the end-of-line. Instead, +chomp() should be used to trim newlines. The Dunce::Files module can +help audit your code for misuses of chop(). + +When dealing with binary files (or text files in binary mode) be sure +to explicitly set $/ to the appropriate value for your file format +before using chomp(). + Because of the "text" mode translation, DOSish perls have limitations in using C and C on a file accessed in "text" mode. Stick to C-ing to locations you got from C (and no @@ -180,11 +200,26 @@ usually either "live" via network connection, or by storing the numbers to secondary storage such as a disk file or tape. Conflicting storage orders make utter mess out of the numbers. If a -little-endian host (Intel, Alpha) stores 0x12345678 (305419896 in -decimal), a big-endian host (Motorola, MIPS, Sparc, PA) reads it as -0x78563412 (2018915346 in decimal). To avoid this problem in network -(socket) connections use the C and C formats C -and C, the "network" orders. These are guaranteed to be portable. +little-endian host (Intel, VAX) stores 0x12345678 (305419896 in +decimal), a big-endian host (Motorola, Sparc, PA) reads it as +0x78563412 (2018915346 in decimal). Alpha and MIPS can be either: +Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses +them in big-endian mode. To avoid this problem in network (socket) +connections use the C and C formats C and C, the +"network" orders. These are guaranteed to be portable. + +You can explore the endianness of your platform by unpacking a +data structure packed in native format such as: + + print unpack("h*", pack("s2", 1, 2)), "\n"; + # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode + # '00100020' on e.g. Motorola 68040 + +If you need to distinguish between endian architectures you could use +either of the variables set like so: + + $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/; + $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/; Differing widths can cause truncation even between platforms of equal endianness. The platform of shorter width loses the upper parts of the @@ -194,8 +229,8 @@ transferring or storing raw binary numbers. One can circumnavigate both these problems in two ways. Either transfer and store numbers always in text format, instead of raw binary, or else consider using modules like Data::Dumper (included in -the standard distribution as of Perl 5.005) and Storable. Keeping -all data as text significantly simplifies matters. +the standard distribution as of Perl 5.005) and Storable (included as +of perl 5.8). Keeping all data as text significantly simplifies matters. =head2 Files and Filesystems @@ -204,7 +239,7 @@ So, it is reasonably safe to assume that all platforms support the notion of a "path" to uniquely identify a file on the system. How that path is really written, though, differs considerably. -Atlhough similar, file path specifications differ between Unix, +Although similar, file path specifications differ between Unix, Windows, S, OS/2, VMS, VOS, S, and probably others. Unix, for example, is one of the few OSes that has the elegant idea of a single root directory. @@ -242,9 +277,13 @@ to be running the program. $file = catfile(curdir(), 'temp', 'file.txt'); # on Unix and Win32, './temp/file.txt' # on Mac OS, ':temp:file.txt' + # on VMS, '[.temp]file.txt' File::Spec is available in the standard distribution as of version -5.004_05. +5.004_05. File::Spec::Functions is only in File::Spec 0.7 and later, +and some versions of perl come with version 0.6. If File::Spec +is not updated to 0.7 or later, you must use the object-oriented +interface from File::Spec (or upgrade File::Spec). In general, production code should not have file paths hardcoded. Making them user-supplied or read from a configuration file is @@ -286,15 +325,15 @@ first 8 characters. Whitespace in filenames is tolerated on most systems, but not all. Many systems (DOS, VMS) cannot have more than one C<.> in their filenames. -Don't assume C> won't be the first character of a filename. -Always use C> explicitly to open a file for reading, +Don't assume C<< > >> won't be the first character of a filename. +Always use C<< < >> explicitly to open a file for reading, unless you want the user to be able to specify a pipe open. open(FILE, "< $existing_file") or die $!; If filenames might use strange characters, it is safest to open it with C instead of C. C is magic and can -translate characters like C>, C>, and C<|>, which may +translate characters like C<< > >>, C<< < >>, and C<|>, which may be the wrong thing to do. (Sometimes, though, it's the right thing.) =head2 System Interaction @@ -313,11 +352,33 @@ file already tied or opened; C or C it first. Don't open the same file more than once at a time for writing, as some operating systems put mandatory locks on such files. +Don't assume that write/modify permission on a directory gives the +right to add or delete files/directories in that directory. That is +filesystem specific: in some filesystems you need write/modify +permission also (or even just) in the file/directory itself. In some +filesystems (AFS, DFS) the permission to add/delete directory entries +is a completely separate permission. + +Don't assume that a single C completely gets rid of the file: +some filesystems (most notably the ones in VMS) have versioned +filesystems, and unlink() removes only the most recent one (it doesn't +remove all the versions because by default the native tools on those +platforms remove just the most recent version, too). The portable +idiom to remove all the versions of a file is + + 1 while unlink "file"; + +This will terminate if the file is undeleteable for some reason +(protected, not there, and so on). + Don't count on a specific environment variable existing in C<%ENV>. Don't count on C<%ENV> entries being case-sensitive, or even -case-preserving. +case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or, +if you really have to, make it conditional on C<$^O ne 'VMS'> since in +VMS the C<%ENV> table is much more than a per-process key-value string +table. -Don't count on signals for anything. +Don't count on signals or C<%SIG> for anything. Don't count on filename globbing. Use C, C, and C instead. @@ -338,7 +399,7 @@ Commands that launch external processes are generally supported on most platforms (though many of them do not support any type of forking). The problem with using them arises from what you invoke them on. External tools are often named differently on different -platforms, may not be available in the same location, migth accept +platforms, may not be available in the same location, might accept different arguments, can behave differently, and often present their results in a platform-dependent way. Thus, you should seldom depend on them to produce consistent results. (Then again, if you're calling @@ -362,6 +423,14 @@ simple, platform-independent mailing. The Unix System V IPC (C) is not available even on all Unix platforms. +Do not use either the bare result of C or +bare v-strings (such as C) to represent IPv4 addresses: +both forms just pack the four bytes into network order. That this +would be equal to the C language C struct (which is what the +socket code internally uses) is not guaranteed. To be portable use +the routines of the Socket extension, such as C, +C, and C. + The rule of thumb for portable code is: Do it all in portable Perl, or use a module (that may internally implement it with platform-specific code, but expose a common interface). @@ -490,7 +559,7 @@ often happens when tests spawn off other processes or call external programs to aid in the testing, or when (as noted above) the tests assume certain things about the filesystem and paths. Be careful not to depend on a specific output style for errors, such as when -checking C<$!> after an system call. Some platforms expect a certain +checking C<$!> after a system call. Some platforms expect a certain output format, and perl on those platforms may have been adjusted accordingly. Most specifically, don't anchor a regex when testing an error value. @@ -511,7 +580,7 @@ a given module works on a given platform. =item Mailing list: cpan-testers@perl.org -=item Testing results: C +=item Testing results: http://testers.cpan.org/ =back @@ -534,10 +603,11 @@ edited after the fact. Perl works on a bewildering variety of Unix and Unix-like platforms (see e.g. most of the files in the F directory in the source code kit). On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>, -too) is determined by lowercasing and stripping punctuation from the first -field of the string returned by typing C (or a similar command) -at the shell prompt. Here, for example, are a few of the more popular -Unix flavors: +too) is determined either by lowercasing and stripping punctuation from the +first field of the string returned by typing C (or a similar command) +at the shell prompt or by testing the file system for the presence of +uniquely named files such as a kernel or header file. Here, for example, +are a few of the more popular Unix flavors: uname $^O $Config{'archname'} -------------------------------------------- @@ -546,11 +616,16 @@ Unix flavors: dgux dgux AViiON-dgux DYNIX/ptx dynixptx i386-dynixptx FreeBSD freebsd freebsd-i386 + Linux linux arm-linux Linux linux i386-linux Linux linux i586-linux Linux linux ppc-linux HP-UX hpux PA-RISC1.1 IRIX irix irix + Mac OS X darwin darwin + MachTen PPC machten powerpc-machten + NeXT 3 next next-fat + NeXT 4 next OPENSTEP-Mach openbsd openbsd i386-openbsd OSF1 dec_osf alpha-dec_osf reliantunix-n svr4 RM400-svr4 @@ -615,30 +690,73 @@ often assume nothing about their data. The C<$^O> variable and the C<$Config{archname}> values for various DOSish perls are as follows: - OS $^O $Config{'archname'} - -------------------------------------------- - MS-DOS dos - PC-DOS dos - OS/2 os2 - Windows 95 MSWin32 MSWin32-x86 - Windows 98 MSWin32 MSWin32-x86 - Windows NT MSWin32 MSWin32-x86 - Windows NT MSWin32 MSWin32-ALPHA - Windows NT MSWin32 MSWin32-ppc + OS $^O $Config{archname} ID Version + -------------------------------------------------------- + MS-DOS dos ? + PC-DOS dos ? + OS/2 os2 ? + Windows 3.1 ? ? 0 3 01 + Windows 95 MSWin32 MSWin32-x86 1 4 00 + Windows 98 MSWin32 MSWin32-x86 1 4 10 + Windows ME MSWin32 MSWin32-x86 1 ? + Windows NT MSWin32 MSWin32-x86 2 4 xx + Windows NT MSWin32 MSWin32-ALPHA 2 4 xx + Windows NT MSWin32 MSWin32-ppc 2 4 xx + Windows 2000 MSWin32 MSWin32-x86 2 5 xx + Windows XP MSWin32 MSWin32-x86 2 ? + Windows CE MSWin32 ? 3 + Cygwin cygwin ? + +The various MSWin32 Perl's can distinguish the OS they are running on +via the value of the fifth element of the list returned from +Win32::GetOSVersion(). For example: + + if ($^O eq 'MSWin32') { + my @os_version_info = Win32::GetOSVersion(); + print +('3.1','95','NT')[$os_version_info[4]],"\n"; + } Also see: =over 4 -=item The djgpp environment for DOS, C +=item * + +The djgpp environment for DOS, http://www.delorie.com/djgpp/ +and L. + +=item * + +The EMX environment for DOS, OS/2, etc. emx@iaehv.nl, +http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or +ftp://hobbes.nmsu.edu/pub/os2/dev/emx. Also L. + +=item * + +Build instructions for Win32 in L, or under the Cygnus environment +in L. + +=item * + +The C modules in L. + +=item * + +The ActiveState Pages, http://www.activestate.com/ + +=item * -=item The EMX environment for DOS, OS/2, etc. C, -C or -C +The Cygwin environment for Win32; F (installed +as L), http://www.cygwin.com/ -=item Build instructions for Win32, L. +=item * -=item The ActiveState Pages, C +The U/WIN environment for Win32, +http://www.research.att.com/sw/tools/uwin/ + +=item * + +Build instructions for OS/2, L =back @@ -698,30 +816,32 @@ the application or MPW tool version is running, check: $is_ppc = $MacPerl::Architecture eq 'MacPPC'; $is_68k = $MacPerl::Architecture eq 'Mac68K'; -S and S, based on NeXT's OpenStep OS, will -(in theory) be able to run MacPerl natively, under the "Classic" -environment. The new "Cocoa" environment (formerly called the "Yellow Box") -may run a slightly modified version of MacPerl, using the Carbon interfaces. - -S and its Open Source version, Darwin, both run Unix -perl natively (with a few patches). Full support for these -is slated for perl 5.6. +S, based on NeXT's OpenStep OS, runs MacPerl natively, under the +"Classic" environment. There is no "Carbon" version of MacPerl to run +under the primary Mac OS X environment. S and its Open Source +version, Darwin, both run Unix perl natively. Also see: =over 4 -=item The MacPerl Pages, C. +=item * + +MacPerl Development, http://dev.macperl.org/ . -=item The MacPerl mailing lists, C. +=item * -=item MacPerl Module Porters, C. +The MacPerl Pages, http://www.macperl.com/ . + +=item * + +The MacPerl mailing lists, http://lists.perl.org/ . =back =head2 VMS -Perl on VMS is discussed in F in the perl distribution. +Perl on VMS is discussed in L in the perl distribution. Perl on VMS can accept either VMS- or Unix-style file specifications as in either of the following: @@ -756,7 +876,7 @@ you are so inclined. For example: $ endif Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your -perl-in-DCL script expects to do things like C<$read = ESTDINE;>. +perl-in-DCL script expects to do things like C<< $read = ; >>. Filenames are in the format "name.extension;version". The maximum length for filenames is 39 characters, and the maximum length for @@ -782,10 +902,11 @@ process on VMS, is a pure Perl module that can easily be installed on non-VMS platforms and can be helpful for conversions to and from RMS native formats. -What C<\n> represents depends on the type of file opened. It could -be C<\015>, C<\012>, C<\015\012>, or nothing. Reading from a file -translates newlines to C<\012>, unless C was executed on that -handle, just like DOSish perls. +What C<\n> represents depends on the type of file opened. It usually +represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>, +C<\000>, C<\040>, or nothing depending on the file organiztion and +record format. The VMS::Stdio module provides access to the +special fopen() requirements of files with unusual attributes on VMS. TCP/IP stacks are optional on VMS, so socket routines might not be implemented. UDP sockets may not be supported. @@ -813,21 +934,27 @@ Also see: =over 4 -=item L +=item * + +F (installed as L), L -=item vmsperl list, C +=item * -Put the words C in message body. +vmsperl list, majordomo@perl.org -=item vmsperl on the web, C +(Put the words C in message body.) + +=item * + +vmsperl on the web, http://www.sidhe.org/vmsperl/index.html =back =head2 VOS -Perl on VOS is discussed in F in the perl distribution. -Perl on VOS can accept either VOS- or Unix-style file -specifications as in either of the following: +Perl on VOS is discussed in F in the perl distribution +(installed as L). Perl on VOS can accept either VOS- or +Unix-style file specifications as in either of the following: $ perl -ne "print if /perl_setup/i" >system>notices $ perl -ne "print if /perl_setup/i" /system/notices @@ -840,20 +967,20 @@ Even though VOS allows the slash character to appear in object names, because the VOS port of Perl interprets it as a pathname delimiting character, VOS files, directories, or links whose names contain a slash character cannot be processed. Such files must be -renamed before they can be processed by Perl. +renamed before they can be processed by Perl. Note that VOS limits +file names to 32 or fewer characters. -The following C functions are unimplemented on VOS, and any attempt by -Perl to use them will result in a fatal error message and an immediate -exit from Perl: dup, do_aspawn, do_spawn, fork, waitpid. Once these -functions become available in the VOS POSIX.1 implementation, you can -either recompile and rebind Perl, or you can download a newer port from -ftp.stratus.com. +See F for restrictions that apply when Perl is built +with the alpha version of VOS POSIX.1 support. + +Perl on VOS is built without any extensions and does not support +dynamic loading. The value of C<$^O> on VOS is "VOS". To determine the architecture that you are running on without resorting to loading all of C<%Config> you -can examine the content of the C<@INC> array like so: +can examine the content of the @INC array like so: - if (grep(/VOS/, @INC)) { + if ($^O =~ /VOS/) { print "I'm on a Stratus box!\n"; } else { print "I'm not on a Stratus box!\n"; @@ -864,40 +991,48 @@ can examine the content of the C<@INC> array like so: print "This box is a Stratus XA/R!\n"; } elsif (grep(/7100/, @INC)) { - print "This box is a Stratus HP 7100 or 8000!\n"; + print "This box is a Stratus HP 7100 or 8xxx!\n"; } elsif (grep(/8000/, @INC)) { - print "This box is a Stratus HP 8000!\n"; + print "This box is a Stratus HP 8xxx!\n"; } else { - print "This box is a Stratus 68K...\n"; + print "This box is a Stratus 68K!\n"; } Also see: =over 4 -=item L +=item * + +F + +=item * -=item VOS mailing list +The VOS mailing list. There is no specific mailing list for Perl on VOS. You can post comments to the comp.sys.stratus newsgroup, or subscribe to the general Stratus mailing list. Send a letter with "Subscribe Info-Stratus" in the message body to majordomo@list.stratagy.com. -=item VOS Perl on the web at C +=item * + +VOS Perl on the web at http://ftp.stratus.com/pub/vos/vos.html =back =head2 EBCDIC Platforms Recent versions of Perl have been ported to platforms such as OS/400 on -AS/400 minicomputers as well as OS/390 & VM/ESA for IBM Mainframes. Such -computers use EBCDIC character sets internally (usually Character Code -Set ID 00819 for OS/400 and IBM-1047 for OS/390 & VM/ESA). On -the mainframe perl currently works under the "Unix system services -for OS/390" (formerly known as OpenEdition) and VM/ESA OpenEdition. +AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390 +Mainframes. Such computers use EBCDIC character sets internally (usually +Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390 +systems). On the mainframe perl currently works under the "Unix system +services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or +the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater). +See L for details. As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix sub-systems do not support the C<#!> shebang trick for script invocation. @@ -911,6 +1046,10 @@ similar to the following simple script: print "Hello from perl!\n"; +OS/390 will support the C<#!> shebang trick in release 2.8 and beyond. +Calls to C and backticks can use POSIX shell syntax on all +S/390 systems. + On the AS/400, if PERL5 is in your library list, you may need to wrap your perl scripts in a CL procedure to invoke them like so: @@ -935,9 +1074,14 @@ translate the C<\n> in the following statement to its ASCII equivalent print "Content-type: text/html\r\n\r\n"; -The value of C<$^O> on OS/390 is "os390". +The values of C<$^O> on some of these platforms includes: -The value of C<$^O> on VM/ESA is "vmesa". + uname $^O $Config{'archname'} + -------------------------------------------- + OS/390 os390 os390 + OS400 os400 os400 + POSIX-BC posix-bc BS2000-posix-bc + VM/ESA vmesa vmesa Some simple tricks for determining if you are running on an EBCDIC platform could include any of the following (perhaps all): @@ -957,13 +1101,24 @@ Also see: =over 4 -=item perl-mvs list +=item * + +* + +L, F, F, F, +L. + +=item * The perl-mvs@perl.org list is for discussion of porting issues as well as general usage issues for all EBCDIC Perls. Send a message body of "subscribe perl-mvs" to majordomo@perl.org. -=item AS/400 Perl information at C +=item * + +AS/400 Perl information at +http://as400.rochester.ibm.com/ +as well as on CPAN in the F directory. =back @@ -1008,9 +1163,9 @@ C until a name is made that points to an object on disk. Writing to a new file C would be allowed only if C contains a single item list. The filesystem will also expand system variables in filenames if enclosed in angle brackets, so -CSystem$DirE.Modules> would look for the file +C<< .Modules >> would look for the file S>. The obvious implication of this is -that BE>> and should +that B >>> and should be protected when C is used for input. Because C<.> was in use as a directory separator and filenames could not @@ -1050,11 +1205,11 @@ library emulates Unix filehandles. Consequently, you can't rely on passing C, C, or C to your children. The desire of users to express filenames of the form -CFoo$DirE.Bar> on the command line unquoted causes problems, +C<< .Bar >> on the command line unquoted causes problems, too: C<``> command output capture has to perform a guessing game. It -assumes that a string C[^EE]+\$[^EE]E> is a +assumes that a string C<< <[^<>]+\$[^<>]> >> is a reference to an environment variable, whereas anything else involving -C> or C> is redirection, and generally manages to be 99% +C<< < >> or C<< > >> is redirection, and generally manages to be 99% right. Of course, the problem remains that scripts cannot rely on any Unix tools being available, or that any tools found have Unix-like command line arguments. @@ -1081,20 +1236,46 @@ for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware, Tandem Guardian, I (Yes, we know that some of these OSes may fall under the Unix category, but we are not a standards body.) +Some approximate operating system names and their C<$^O> values +in the "OTHER" category include: + + OS $^O $Config{'archname'} + ------------------------------------------ + Amiga DOS amigaos m68k-amigos + MPE/iX mpeix PA-RISC1.1 + See also: =over 4 -=item Atari, Guido Flohr's page C +=item * + +Amiga, F (installed as L). + +=item * -=item HP 300 MPE/iX C +Atari, F and Guido Flohr's web page +http://stud.uni-sb.de/~gufl0000/ -=item Novell Netware +=item * + +Be OS, F + +=item * + +HP 300 MPE/iX, F and Mark Bixby's web page +http://www.bixby.org/mark/perlix.html + +=item * A free perl5-based PERL.NLM for Novell Netware is available in -precompiled binary and source code form from C +precompiled binary and source code form from http://www.novell.com/ as well as from CPAN. +=item * + +Plan 9, F + =back =head1 FUNCTION IMPLEMENTATIONS @@ -1162,6 +1343,12 @@ suffixes. C<-S> is meaningless. (Win32) C<-x> (or C<-X>) determine if a file has an executable file type. (S) +=item alarm SECONDS + +=item alarm + +Not implemented. (Win32) + =item binmode FILEHANDLE Meaningless. (S, S) @@ -1226,6 +1413,20 @@ Not implemented. (S) Implemented via Spawn. (VM/ESA) +Does not automatically flush output handles on some platforms. +(SunOS, Solaris, HP-UX) + +=item exit EXPR + +=item exit + +Emulates UNIX exit() (which considers C to indicate an error) by +mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden +with the pragma C. As with the CRTL's exit() +function, C is also mapped to an exit status of SS$_NORMAL +(C<1>); this mapping cannot be overridden. Any other argument to exit() +is used directly as Perl's exit status. (VMS) + =item fcntl FILEHANDLE,FUNCTION,SCALAR Not implemented. (Win32, VMS) @@ -1238,7 +1439,12 @@ Available only on Windows NT (not on Windows 95). (Win32) =item fork -Not implemented. (S, Win32, AmigaOS, S, VOS, VM/ESA) +Not implemented. (S, AmigaOS, S, VOS, VM/ESA) + +Emulated using multiple interpreters. See L. (Win32) + +Does not automatically flush output handles on some platforms. +(SunOS, Solaris, HP-UX) =item getlogin @@ -1342,11 +1548,11 @@ Not implemented. (Plan9, Win32, S) =item endpwent -Not implemented. (S, Win32, VM/ESA) +Not implemented. (S, MPE/iX, VM/ESA, Win32) =item endgrent -Not implemented. (S, Win32, VMS, S, VM/ESA) +Not implemented. (S, MPE/iX, S, VM/ESA, VMS, Win32) =item endhostent @@ -1366,23 +1572,14 @@ Not implemented. (Plan9, Win32) =item getsockopt SOCKET,LEVEL,OPTNAME -Not implemented. (S, Plan9) +Not implemented. (Plan9) =item glob EXPR =item glob -Globbing built-in, but only C<*> and C metacharacters are supported. -(S) - -Features depend on external perlglob.exe or perlglob.bat. May be -overridden with something like File::DosGlob, which is recommended. -(Win32) - -Globbing built-in, but only C<*> and C metacharacters are supported. -Globbing relies on operating system calls, which may return filenames -in any order. As most filesystems are case-insensitive, even "sorted" -filenames will not be in case-sensitive order. (S) +This operator is implemented via the File::Glob extension on most +platforms. See L for portability information. =item ioctl FILEHANDLE,FUNCTION,SCALAR @@ -1393,21 +1590,30 @@ in the Winsock API does. (Win32) Available only for socket handles. (S) -=item kill LIST +=item kill SIGNAL, LIST + +C is implemented for the sake of taint checking; +use with other signals is unimplemented. (S) -Not implemented, hence not useful for taint checking. (S, -S) +Not implemented, hence not useful for taint checking. (S) -Available only for process handles returned by the C -method of spawning a process. (Win32) +C doesn't have the semantics of C, i.e. it doesn't send +a signal to the identified process like it does on Unix platforms. +Instead C terminates the process identified by $pid, +and makes it exit immediately with exit status $sig. As in Unix, if +$sig is 0 and the specified process exists, it returns true without +actually terminating it. (Win32) =item link OLDFILE,NEWFILE -Not implemented. (S, Win32, VMS, S) +Not implemented. (S, MPE/iX, VMS, S) Link count not updated because hard links are not quite that hard (They are sort of half-way between hard and soft links). (AmigaOS) +Hard links are implemented on Win32 (Windows NT and Windows 2000) +under NTFS only. + =item lstat FILEHANDLE =item lstat EXPR @@ -1416,7 +1622,7 @@ Link count not updated because hard links are not quite that hard Not implemented. (VMS, S) -Return values may be bogus. (Win32) +Return values (especially for device and inode) may be bogus. (Win32) =item msgctl ID,CMD,ARG @@ -1437,9 +1643,10 @@ The C<|> variants are supported only if ToolServer is installed. open to C<|-> and C<-|> are unsupported. (S, Win32, S) -=item pipe READHANDLE,WRITEHANDLE +Opening a process does not automatically flush output handles on some +platforms. (SunOS, Solaris, HP-UX) -Not implemented. (S) +=item pipe READHANDLE,WRITEHANDLE Very limited functionality. (MiNT) @@ -1451,10 +1658,12 @@ Not implemented. (Win32, VMS, S) =item select RBITS,WBITS,EBITS,TIMEOUT -Only implemented on sockets. (Win32) +Only implemented on sockets. (Win32, VMS) Only reliable on sockets. (S) +Note that the C