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(<FILE>) {
- chop;
- @array = split(/:/);
- #...
- }
-
-You can get away with this on Unix and Mac OS (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 L<Dunce::Files> module
-can help audit your code for misuses of chop().
+To trim trailing newlines from text lines use chomp(). With default
+settings that function looks for a trailing C<\n> character and thus
+trims in a portable way.
When dealing with binary files (or text files in binary mode) be sure
to explicitly set $/ to the appropriate value for your file format
VMS the C<%ENV> table is much more than a per-process key-value string
table.
+On VMS, some entries in the %ENV hash are dynamically created when
+their key is used on a read if they did not previously exist. The
+values for C<$ENV{HOME}>, C<$ENV{TERM}>, C<$ENV{HOME}>, and C<$ENV{USER}>,
+are known to be dynamically generated. The specific names that are
+dynamically generated may vary with the version of the C library on VMS,
+and more may exist than is documented.
+
+On VMS by default, changes to the %ENV hash are persistent after the process
+exits. This can cause unintended issues.
+
Don't count on signals or C<%SIG> for anything.
Don't count on filename globbing. Use C<opendir>, C<readdir>, and
later. If the bytes are native 8-bit bytes, you can use the C<bytes>
pragma. If the bytes are in a string (regular expression being a
curious string), you can often also use the C<\xHH> notation instead
-of embedding the bytes as-is. If they are in some particular legacy
-encoding (ether single-byte or something more complicated), you can
-use the C<encoding> pragma. (If you want to write your code in UTF-8,
-you can use either the C<utf8> pragma, or the C<encoding> pragma.)
-The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
-the C<encoding> pragma since Perl 5.8.0.
+of embedding the bytes as-is. (If you want to write your code in UTF-8,
+you can use the C<utf8>.) The C<bytes> and C<utf8> pragmata are
+available since Perl 5.6.0.
=head2 System Resources
again with the optionally the exact case.
RMS had an eight level limit on directory depths from any rooted logical
-(allowing 16 levels overall) prior to VMS 7.2. Hence
-C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
-C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
-have to take this into account, but at least they can refer to the former
-as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
+(allowing 16 levels overall) prior to VMS 7.2, and even with versions of
+VMS on VAX up through 7.3. Hence C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a
+valid directory specification but C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is
+not. F<Makefile.PL> authors might have to take this into account, but at
+least they can refer to the former as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
+
+Pumpkings and module integrators can easily see whether files with too many
+directory levels have snuck into the core by running the following in the
+top-level source directory:
+
+ $ perl -ne "$_=~s/\s+.*//; print if scalar(split /\//) > 8;" < MANIFEST
+
The VMS::Filespec module, which gets installed as part of the build
process on VMS, is a pure Perl module that can easily be installed on
=item *
-vmsperl list, majordomo@perl.org
-
-(Put the words C<subscribe vmsperl> in message body.)
+vmsperl list, vmsperl-subscribe@perl.org
=item *
Not useful. (S<Mac OS>, S<RISC OS>)
-Not implemented. (Win32)
+Not supported. (Cygwin, Win32)
Invokes VMS debugger. (VMS)
$sig is 0 and the specified process exists, it returns true without
actually terminating it. (Win32)
+C<kill(-9, $pid)> will terminate the process specified by $pid and
+recursively all child processes owned by it. This is different from
+the Unix semantics, where the signal will be delivered to all
+processes in the same process group as the process specified by
+$pid. (Win32)
+
Is not supported for process identification number of 0 or negative
numbers. (VMS)
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.
+Hard links are implemented on Win32 under NTFS only. They are
+natively supported on Windows 2000 and later. On Windows NT they
+are implemented using the Windows POSIX subsystem support and the
+Perl process will need Administrator or Backup Operator privileges
+to create hard links.
Available on 64 bit OpenVMS 8.2 and later. (VMS)
=item socketpair
-Not implemented. (Win32, S<RISC OS>, VOS, VM/ESA)
+Not implemented. (S<RISC OS>, VOS, VM/ESA)
Available on 64 bit OpenVMS 8.2 and later. (VMS)
some versions of cygwin when doing a stat("foo") and if not finding it
may then attempt to stat("foo.exe") (Cygwin)
+On Win32 stat() needs to open the file to determine the link count
+and update attributes that may have been changed through hard links.
+Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up stat() by
+not performing this operation. (Win32)
+
=item symlink
-Not implemented. (Win32, VMS, S<RISC OS>)
+Not implemented. (Win32, S<RISC OS>)
+
+Implemented on 64 bit VMS 8.3. VMS requires the symbolic link to be in Unix
+syntax if it is intended to resolve to a valid path.
=item syscall
https://perl5.git.perl.org / perl5.git / blobdiff