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<unlink> 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. Don't try to clear %ENV by saying C<%ENV = ();>, or,
The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
even on all Unix platforms.
+Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
+bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
+both forms just pack the four bytes into network order. That this
+would be equal to the C language C<in_addr> 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<inet_aton()>,
+C<inet_ntoa()>, and C<sockaddr_in()>.
+
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).
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.
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
- Cygwin cygwin
+ OS $^O $Config{archname} ID Version
+ --------------------------------------------------------
+ MS-DOS dos ?
+ PC-DOS dos ?
+ OS/2 os2 ?
+ Windows 3.1 ? ? 0 3 01
+ Windows 95 MSWin32 MSWin32-x86 1 4 00
+ Windows 98 MSWin32 MSWin32-x86 1 4 10
+ Windows ME MSWin32 MSWin32-x86 1 ?
+ Windows NT MSWin32 MSWin32-x86 2 4 xx
+ Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
+ Windows NT MSWin32 MSWin32-ppc 2 4 xx
+ Windows 2000 MSWin32 MSWin32-x86 2 5 xx
+ Windows XP MSWin32 MSWin32-x86 2 ?
+ Windows CE MSWin32 ? 3
+ Cygwin cygwin ?
The various MSWin32 Perl's can distinguish the OS they are running on
via the value of the fifth element of the list returned from
=item *
-The MacPerl Pages, http://www.macperl.com/ .
+MacPerl Development, http://dev.macperl.org/ .
=item *
-The MacPerl mailing lists, http://www.macperl.org/ .
+The MacPerl Pages, http://www.macperl.com/ .
=item *
-MacPerl Module Porters, http://pudge.net/mmp/ .
+The MacPerl mailing lists, http://lists.perl.org/ .
=back
Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)
+=item exit EXPR
+
+=item exit
+
+Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
+mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
+with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
+function, C<exit 0> 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)
=item getsockopt SOCKET,LEVEL,OPTNAME
-Not implemented. (S<Mac OS>, Plan9)
+Not implemented. (Plan9)
=item glob EXPR
=item glob
-Globbing built-in, but only C<*> and C<?> metacharacters are supported.
-(S<Mac OS>)
-
This operator is implemented via the File::Glob extension on most
platforms. See L<File::Glob> for portability information.
=item kill SIGNAL, LIST
-Not implemented, hence not useful for taint checking. (S<Mac OS>,
-S<RISC OS>)
+C<kill(0, LIST)> is implemented for the sake of taint checking;
+use with other signals is unimplemented. (S<Mac OS>)
+
+Not implemented, hence not useful for taint checking. (S<RISC OS>)
C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
a signal to the identified process like it does on Unix platforms.
=item pipe READHANDLE,WRITEHANDLE
-Not implemented. (S<Mac OS>)
-
Very limited functionality. (MiNT)
=item readlink EXPR
=item select RBITS,WBITS,EBITS,TIMEOUT
-Only implemented on sockets. (Win32)
+Only implemented on sockets. (Win32, VMS)
Only reliable on sockets. (S<RISC OS>)
-Note that the C<socket FILEHANDLE> form is generally portable.
+Note that the C<select FILEHANDLE> form is generally portable.
=item semctl ID,SEMNUM,CMD,ARG
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
-Not implemented. (S<Mac OS>, Plan9)
+Not implemented. (Plan9)
=item shmctl ID,CMD,ARG
=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
+Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
=item stat FILEHANDLE
dev, rdev, blksize, and blocks are not available. inode is not
meaningful and will differ between stat calls on the same file. (os2)
+some versions of cygwin when doing a stat("foo") and if not finding it
+may then attempt to stat("foo.exe") (Cygwin)
+
=item symlink OLDFILE,NEWFILE
Not implemented. (Win32, VMS, S<RISC OS>)
Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)
+The return value is POSIX-like (shifted up by 8 bits), which only allows
+room for a made-up value derived from the severity bits of the native
+32-bit condition code (unless overridden by C<use vmsish 'status'>).
+For more details see L<perlvms/$?>. (VMS)
+
=item times
Only the first entry returned is nonzero. (S<Mac OS>)
=item truncate EXPR,LENGTH
-Not implemented. (VMS)
+Not implemented. (Older versions of VMS)
Truncation to zero-length only. (VOS)
If a FILEHANDLE is supplied, it must be writable and opened in append
-mode (i.e., use C<open(FH, '>>filename')>
+mode (i.e., use C<<< open(FH, '>>filename') >>>
or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
should not be held open elsewhere. (Win32)
As of early 2001 (the Perl releases 5.6.1 and 5.7.1), the following
platforms are able to build Perl from the standard source code
-distribution available at http://www.perl.com/CPAN/src/index.html
+distribution available at http://www.cpan.org/src/index.html
AIX
AmigaOS
1) in DOS mode either the DOS or OS/2 ports can be used
2) Mac OS Classic (pre-X) is almost 5.6.1-ready; building from
the source does work with 5.6.1, but additional MacOS specific
- source code is needed for a complete build. Contact the mailing
- list macperl-porters@macperl.org for more information.
+ source code is needed for a complete build. See the web
+ site http://dev.macperl.org/ for more information.
3) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
The following platforms worked for the previous releases (5.6.0 and 5.7.0),
Netware
The following platforms have their own source code distributions and
-binaries available via http://www.perl.com/CPAN/ports/index.html:
+binaries available via http://www.cpan.org/ports/index.html:
Perl release
Tandem Guardian 5.004
The following platforms have only binaries available via
-http://www.perl.com/CPAN/ports/index.html :
+http://www.cpan.org/ports/index.html :
Perl release
Although we do suggest that you always build your own Perl from
the source code, both for maximal configurability and for security,
in case you are in a hurry you can check
-http://www.perl.com/CPAN/ports/index.html for binary distributions.
+http://www.cpan.org/ports/index.html for binary distributions.
=head1 SEE ALSO
L<perlaix>, L<perlapollo>, L<perlamiga>, L<perlbeos>, L<perlbs200>,
-L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
+L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
L<perlhurd>, L<perlhpux>, L<perlmachten>, L<perlmacos>, L<perlmint>,
L<perlmpeix>, L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>,
L<perlqnx>, L<perlsolaris>, L<perltru64>, L<perlunicode>,
Paul Moore <Paul.Moore@uk.origin-it.com>,
Chris Nandor <pudge@pobox.com>,
Matthias Neeracher <neeri@iis.ee.ethz.ch>,
+Philip Newton <pne@cpan.org>,
Gary Ng <71564.1743@CompuServe.COM>,
Tom Phoenix <rootbeer@teleport.com>,
AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
projects / p5sagit/p5-mst-13.2.git / blobdiff