perlport.pod

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=item glob EXPR

=item glob

This operator is implemented via the File::Glob extension on most
platforms.  See L<File::Glob> for portability information.

=item ioctl FILEHANDLE,FUNCTION,SCALAR

Not implemented. (VMS)

Available only for socket handles, and it does what the ioctlsocket() call
in the Winsock API does. (Win32)

Available only for socket handles. (S<RISC OS>)

=item kill SIGNAL, LIST

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.
Instead C<kill($sig, $pid)> 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<Mac OS>, MPE/iX, VMS, S<RISC OS>)

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

=item lstat

Not implemented. (VMS, S<RISC OS>)

Return values (especially for device and inode) may be bogus. (Win32)

=item msgctl ID,CMD,ARG

=item msgget KEY,FLAGS

=item msgsnd ID,MSG,FLAGS

=item msgrcv ID,VAR,SIZE,TYPE,FLAGS

Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)

=item open FILEHANDLE,EXPR

=item open FILEHANDLE

The C<|> variants are supported only if ToolServer is installed.
(S<Mac OS>)

open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)

Opening a process does not automatically flush output handles on some
platforms.  (SunOS, Solaris, HP-UX)

=item pipe READHANDLE,WRITEHANDLE

Very limited functionality. (MiNT)

=item readlink EXPR

=item readlink

Not implemented. (Win32, VMS, S<RISC OS>)

=item select RBITS,WBITS,EBITS,TIMEOUT

Only implemented on sockets. (Win32)

Only reliable on sockets. (S<RISC OS>)

Note that the C<socket FILEHANDLE> form is generally portable.

=item semctl ID,SEMNUM,CMD,ARG

=item semget KEY,NSEMS,FLAGS

=item semop KEY,OPSTRING

Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)

=item setgrent

Not implemented. (MPE/iX, Win32)

=item setpgrp PID,PGRP

Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)

=item setpriority WHICH,WHO,PRIORITY

Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)

=item setpwent

Not implemented. (MPE/iX, Win32)

=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL

Not implemented. (S<Mac OS>, Plan9)

=item shmctl ID,CMD,ARG

=item shmget KEY,SIZE,FLAGS

=item shmread ID,VAR,POS,SIZE

=item shmwrite ID,STRING,POS,SIZE

Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)

=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL

Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)

=item stat FILEHANDLE

=item stat EXPR

=item stat

Platforms that do not have rdev, blksize, or blocks will return these
as '', so numeric comparison or manipulation of these fields may cause
'not numeric' warnings.

mtime and atime are the same thing, and ctime is creation time instead of
inode change time. (S<Mac OS>)

device and inode are not meaningful.  (Win32)

device and inode are not necessarily reliable.  (VMS)

mtime, atime and ctime all return the last modification time.  Device and
inode are not necessarily reliable.  (S<RISC OS>)

dev, rdev, blksize, and blocks are not available.  inode is not
meaningful and will differ between stat calls on the same file.  (os2)

=item symlink OLDFILE,NEWFILE

Not implemented. (Win32, VMS, S<RISC OS>)

=item syscall LIST

Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)

=item sysopen FILEHANDLE,FILENAME,MODE,PERMS

The traditional "0", "1", and "2" MODEs are implemented with different
numeric values on some systems.  The flags exported by C<Fcntl>
(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though.  (S<Mac
OS>, OS/390, VM/ESA)

=item system LIST

Only implemented if ToolServer is installed. (S<Mac OS>)

As an optimization, may not call the command shell specified in
C<$ENV{PERL5SHELL}>.  C<system(1, @args)> spawns an external
process and immediately returns its process designator, without
waiting for it to terminate.  Return value may be used subsequently
in C<wait> or C<waitpid>.  Failure to spawn() a subprocess is indicated
by setting $? to "255 << 8".  C<$?> is set in a way compatible with
Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
as described in the documentation).  (Win32)

There is no shell to process metacharacters, and the native standard is
to pass a command line terminated by "\n" "\r" or "\0" to the spawned
program.  Redirection such as C<< > foo >> is performed (if at all) by
the run time library of the spawned program.  C<system> I<list> will call
the Unix emulation library's C<exec> emulation, which attempts to provide
emulation of the stdin, stdout, stderr in force in the parent, providing
the child program uses a compatible version of the emulation library.
I<scalar> will call the native command line direct and no such emulation
of a child Unix program will exists.  Mileage B<will> vary.  (S<RISC OS>)

Far from being POSIX compliant.  Because there may be no underlying
/bin/sh tries to work around the problem by forking and execing the
first token in its argument string.  Handles basic redirection
("<" or ">") on its own behalf. (MiNT)

Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)

=item times

Only the first entry returned is nonzero. (S<Mac OS>)

"cumulative" times will be bogus.  On anything other than Windows NT
or Windows 2000, "system" time will be bogus, and "user" time is
actually the time returned by the clock() function in the C runtime
library. (Win32)

Not useful. (S<RISC OS>)

=item truncate FILEHANDLE,LENGTH

=item truncate EXPR,LENGTH

Not implemented. (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')>
or C<sysopen(FH,...,O_APPEND|O_RDWR)>.  If a filename is supplied, it
should not be held open elsewhere. (Win32)

=item umask EXPR

=item umask

Returns undef where unavailable, as of version 5.005.

C<umask> works but the correct permissions are set only when the file
is finally closed. (AmigaOS)

=item utime LIST

Only the modification time is updated. (S<Mac OS>, VMS, S<RISC OS>)

May not behave as expected.  Behavior depends on the C runtime
library's implementation of utime(), and the filesystem being
used.  The FAT filesystem typically does not support an "access
time" field, and it may limit timestamps to a granularity of
two seconds. (Win32)

=item wait

=item waitpid PID,FLAGS

Not implemented. (S<Mac OS>, VOS)

Can only be applied to process handles returned for processes spawned
using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)

Not useful. (S<RISC OS>)

=back

=head1 CHANGES

=over 4

=item v1.48, 02 February 2001

Various updates from perl5-porters over the past year, supported
platforms update from Jarkko Hietaniemi.

=item v1.47, 22 March 2000

Various cleanups from Tom Christiansen, including migration of 
long platform listings from L<perl>.

=item v1.46, 12 February 2000

Updates for VOS and MPE/iX. (Peter Prymmer)  Other small changes.

=item v1.45, 20 December 1999

Small changes from 5.005_63 distribution, more changes to EBCDIC info.

=item v1.44, 19 July 1999

A bunch of updates from Peter Prymmer for C<$^O> values,
endianness, File::Spec, VMS, BS2000, OS/400.

=item v1.43, 24 May 1999

Added a lot of cleaning up from Tom Christiansen.

=item v1.42, 22 May 1999

Added notes about tests, sprintf/printf, and epoch offsets.

=item v1.41, 19 May 1999

Lots more little changes to formatting and content.

Added a bunch of C<$^O> and related values
for various platforms; fixed mail and web addresses, and added
and changed miscellaneous notes.  (Peter Prymmer)

=item v1.40, 11 April 1999

Miscellaneous changes.

=item v1.39, 11 February 1999

Changes from Jarkko and EMX URL fixes Michael Schwern.  Additional
note about newlines added.

=item v1.38, 31 December 1998

More changes from Jarkko.

=item v1.37, 19 December 1998

More minor changes.  Merge two separate version 1.35 documents.

=item v1.36, 9 September 1998

Updated for Stratus VOS.  Also known as version 1.35.

=item v1.35, 13 August 1998

Integrate more minor changes, plus addition of new sections under
L<"ISSUES">: L<"Numbers endianness and Width">,
L<"Character sets and character encoding">,
L<"Internationalisation">.

=item v1.33, 06 August 1998

Integrate more minor changes.

=item v1.32, 05 August 1998

Integrate more minor changes.

=item v1.30, 03 August 1998

Major update for RISC OS, other minor changes.

=item v1.23, 10 July 1998

First public release with perl5.005.

=back

=head1 Supported Platforms

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

	AIX
	AmigaOS
	Darwin		(Mac OS X)
	DG/UX
	DOS DJGPP 	1)
	DYNIX/ptx
	EPOC
	FreeBSD
	HP-UX
	IRIX
	Linux
	MachTen
	MacOS Classic	2)
	NonStop-UX
	ReliantUNIX	(SINIX)
	OpenBSD
	OpenVMS		(VMS)
	OS/2
	OS X
	QNX
	Solaris
	Tru64 UNIX      (DEC OSF/1, Digital UNIX)
	UNICOS
	UNICOS/mk
	VOS
	Win32/NT/2K	3)

        1) in DOS mode either the DOS or OS/2 ports can be u