[PATCH] Improve documentation to support portability #11379
Comments
From Bo.Johansson@lsn.seFrom be5ca44137a6934c3360c55b259706be328e368e Mon Sep 17 00:00:00 2001 To write portable Perl code there are many things to consider. This patch: 1) Adds information about portability issues in the 2) In perlfork.pod adds a section about kill on forked pod/perlfork.pod | 12 +++++ Inline Patchdiff --git a/pod/perlfork.pod b/pod/perlfork.pod
index 709d053..4eeab97 100644
--- a/pod/perlfork.pod
+++ b/pod/perlfork.pod
@@ -307,6 +307,18 @@ are expected to be fixed for thread-safety.
+=head1 PORTABLE PERL CODE AND KILL OF FORKED PROCESSES =over 8 Inline Patchdiff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 91a19a2..91ab03e 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -430,6 +430,8 @@ C<-x $file && -w _ && -f _>. (This is only fancy fancy: if you use
+Portability issues: L<perlport/x>. @@ -500,6 +502,8 @@ modulo the caveats given in L<perlipc/"Signals">. For more information see L<perlipc>. +Portability issues: L<perlport/alarm>. @@ -513,6 +517,8 @@ function, or use the familiar relation: +Portability issues: L<perlport/atan2>. @@ -612,6 +618,8 @@ but also when using read(), seek(), sysread(), syswrite() and tell() +Portability issues: L<perlport/binmode>. @@ -761,6 +769,8 @@ module: +Portability issues: L<perlport/chmod>. @@ -864,6 +874,8 @@ On POSIX systems, you can detect this condition this way: +Portability issues: L<perlport/chmod>. @@ -898,6 +910,8 @@ change your current working directory, which is unaffected.) For security +Portability issues: L<perlport/chroot>. @@ -1089,6 +1103,8 @@ the string back to an eight-bit byte string before calling crypt() +Portability issues: L<perlport/crypt>. @@ -1096,6 +1112,8 @@ X<dbmclose> Breaks the binding between a DBM file and a hash. +Portability issues: L<perlport/dbmclose>. @@ -1139,6 +1157,8 @@ before you call dbmopen(): +Portability issues: L<perlport/dbmopen>. Within a C<foreach> or a C<given>, a C<default> BLOCK acts like a C<when> +Portability issues: L<perlport/dump>. @@ -1802,6 +1824,8 @@ open handles to avoid lost output. +Portability issues: L<perlport/exec>. @@ -1896,6 +1920,8 @@ can change the exit status by modifying C<$?>. If this is a problem, you +Portability issues: L<perlport/exit>. @@ -1941,6 +1967,8 @@ on your own, though. +Portability issues: L<perlport/fcntl>. @@ -2041,6 +2069,8 @@ function lose their locks, making it seriously harder to write servers. See also L<DB_File> for other flock() examples. +Portability issues: L<perlport/flock>. @@ -2070,6 +2100,14 @@ if you exit, then the remote server (such as, say, a CGI script or a +On some platforms such as Windows, where the fork() system call is not available, @@ -2161,6 +2199,8 @@ returns the empty string, use C<getpwuid>. +Portability issues: L<perlport/getlogin>. @@ -2183,6 +2223,8 @@ doesn't implement getpgrp(2). If PID is omitted, returns the process +Portability issues: L<perlport/getpgrp>. @@ -2195,6 +2237,8 @@ C<getppid()>, that returns a consistent value across threads. If you want +Portability issues: L<perlport/getppid>. @@ -2202,6 +2246,8 @@ Returns the current priority for a process, a process group, or a user. +Portability issues: L<perlport/getpriority>. +Portability issues: L<perlport/getpwnam> to L<perlport/endservent>. @@ -2418,6 +2466,7 @@ Here's an example to test whether Nagle's algorithm is enabled on a socket: +Portability issues: L<perlport/getsockopt>. =item given EXPR BLOCK +Portability issues: L<perlport/glob>. @@ -2484,7 +2535,7 @@ Note: When called in list context, $isdst, the last value -See L<perlport/gmtime> for portability concerns. =item goto LABEL +Portability issues: L<perlport/ioctl>. @@ -2771,6 +2824,15 @@ signal the current process group and -1 will signal all processes. See L<perlipc/"Signals"> for more details. +On some platforms such as Windows where the fork() system call is not available. @@ -2897,6 +2959,8 @@ X<link> +Portability issues: L<perlport/link>. @@ -2990,8 +3054,6 @@ try for example: -See L<perlport/localtime> for portability concerns. +Portability issues: L<perlport/localtime>. @@ -3041,6 +3105,8 @@ information, please see the documentation for C<stat>. If EXPR is omitted, stats C<$_>. +Portability issues: L<perlport/lstat>. The match operator. See L<perlop/"Regexp Quote-Like Operators">. +Portability issues: L<perlport/msgctl>. @@ -3173,6 +3241,8 @@ id, or C<undef> on error. See also +Portability issues: L<perlport/msgget>. @@ -3185,6 +3255,8 @@ Taints the variable. Returns true if successful, false +Portability issues: L<perlport/msgrcv>. @@ -3196,6 +3268,8 @@ C<pack("l! a*", $type, $message)>. Returns true if successful, +Portability issues: L<perlport/msgsnd>. @@ -3705,6 +3779,8 @@ yourself and inspect the return value. See L</seek> for some details about mixing reading and writing. +Portability issues: L<perlport/open>. @@ -4823,6 +4899,8 @@ implemented. If not, raises an exception. If there is a system +Portability issues: L<perlport/readlink>. =item readpipe +Portability issues: L<perlport/rename>. @@ -5216,6 +5296,8 @@ X<rewinddir> +Portability issues: L<perlport/rewinddir>. @@ -5374,6 +5456,8 @@ methods, preferring to write the last example as: +Portability issues: L<perlport/select>. @@ -5438,6 +5522,8 @@ B<WARNING>: One should not attempt to mix buffered I/O (like C<read> +Portability issues: L<perlport/select>. @@ -5454,6 +5540,8 @@ short integers, which may be created with C<pack("s!",(0)x$nsem)>. +Portability issues: L<perlport/semctl>. @@ -5462,6 +5550,8 @@ the undefined value on error. See also +Portability issues: L<perlport/semget>. @@ -5480,6 +5570,8 @@ To signal the semaphore, replace C<-1> with C<1>. See also +Portability issues: L<perlport/semop>. @@ -5510,6 +5602,8 @@ it defaults to C<0,0>. Note that the BSD 4.2 version of C<setpgrp> does not +Portability issues: L<perlport/setpgrp>. @@ -5517,6 +5611,8 @@ Sets the current priority for a process, a process group, or a user. +Portability issues: L<perlport/setpriority>. @@ -5531,6 +5627,8 @@ An example disabling Nagle's algorithm on a socket: +Portability issues: L<perlport/setsockopt>. @@ -5568,6 +5666,8 @@ structure. Returns like ioctl: C<undef> for error; "C<0> but +Portability issues: L<perlport/shmctl>. @@ -5575,6 +5675,8 @@ Calls the System V IPC function shmget. Returns the shared memory +Portability issues: L<perlport/shmget>. +Portability issues: L<perlport/shmread> and L<perlport/shmwrite>. @@ -5694,6 +5798,8 @@ See L<perlipc> for an example of socketpair use. Perl 5.8 and later will +Portability issues: L<perlport/socketpair>. @@ -6602,6 +6708,8 @@ See your native chmod(2) and stat(2) documentation for more details +Portability issues: L<perlport/stat>. @@ -6771,6 +6879,8 @@ use eval: $symlink_exists = eval { symlink("",""); 1 }; +Portability issues: L<perlport/symlink>. @@ -6806,6 +6916,8 @@ number of the read end of the pipe it creates, but there is no way +Portability issues: L<perlport/syscall>. @@ -6869,6 +6981,8 @@ library, or perhaps using the POSIX::open() function. See L<perlopentut> for a kinder, gentler explanation of opening files. +Portability issues: L<perlport/sysopen>. @@ -7004,6 +7118,8 @@ See L<perlop/"`STRING`"> and L</exec> for details. +Portability issues: L<perlport/system>. @@ -7198,6 +7314,8 @@ In scalar context, C<times> returns C<$user>. Children's times are only included for terminated children. +Portability issues: L<perlport/times>. The transliteration operator. Same as C<y///>. See +Portability issues: L<perlport/truncate>. @@ -7285,6 +7405,8 @@ not trying to restrict access for yourself, returns C<undef>. +Portability issues: L<perlport/umask>. @@ -7595,6 +7717,8 @@ files. On systems that don't support futimes(2), passing filehandles raises +Portability issues: L<perlport/utime>. @@ -7888,6 +8012,8 @@ being automatically reaped, as described in L<perlipc>. +Portability issues: L<perlport/wait>. @@ -7913,6 +8039,8 @@ Note that on some systems, a return value of C<-1> could mean that child +Portability issues: L<perlport/waitpid>. -- |
From Bo.Johansson@lsn.se(Same message but patch moved to file) To write portable Perl code there are many things to consider. This patch: 1) Adds information about portability issues in the 2) In perlfork.pod adds a section about kill on forked |
From Bo.Johansson@lsn.se0001-Improve-documentation-to-support-portability.patchFrom be5ca44137a6934c3360c55b259706be328e368e Mon Sep 17 00:00:00 2001
From: bojilund <bo.johansso@lsn.se>
Date: Tue, 24 May 2011 15:27:44 +0200
Subject: [PATCH] Improve documentation to support portability
---
pod/perlfork.pod | 12 +++++
pod/perlfunc.pod | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 143 insertions(+), 3 deletions(-)
diff --git a/pod/perlfork.pod b/pod/perlfork.pod
index 709d053..4eeab97 100644
--- a/pod/perlfork.pod
+++ b/pod/perlfork.pod
@@ -307,6 +307,18 @@ are expected to be fixed for thread-safety.
=back
+=head1 PORTABLE PERL CODE AND KILL OF FORKED PROCESSES
+
+In portable Perl code, kill(9, $child) must not be used on forked processes.
+
+Forked process are in Windows implemented as a pseudo-processes.
+To use kill(9, $child) on pseudo-processes is unsafe.
+The process which implements the pseudo-processes can be blocked and the Perl interpreter hangs.
+
+The outcome of kill on a pseudo-process is unpredictable.
+It depends on the timing in the Windows operating system.
+Code that has worked, suddenly can fail, resulting in errors which are difficult to find.
+
=head1 BUGS
=over 8
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 91a19a2..91ab03e 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -430,6 +430,8 @@ C<-x $file && -w _ && -f _>. (This is only fancy fancy: if you use
the return value of C<-f $file> as an argument to another filetest
operator, no special magic will happen.)
+Portability issues: L<perlport/x>.
+
=item abs VALUE
X<abs> X<absolute>
@@ -500,6 +502,8 @@ modulo the caveats given in L<perlipc/"Signals">.
For more information see L<perlipc>.
+Portability issues: L<perlport/alarm>.
+
=item atan2 Y,X
X<atan2> X<arctangent> X<tan> X<tangent>
@@ -513,6 +517,8 @@ function, or use the familiar relation:
The return value for C<atan2(0,0)> is implementation-defined; consult
your atan2(3) manpage for more information.
+Portability issues: L<perlport/atan2>.
+
=item bind SOCKET,NAME
X<bind>
@@ -612,6 +618,8 @@ but also when using read(), seek(), sysread(), syswrite() and tell()
in L<perlvar> for how to manually set your input and output
line-termination sequences.
+Portability issues: L<perlport/binmode>.
+
=item bless REF,CLASSNAME
X<bless>
@@ -761,6 +769,8 @@ module:
chmod S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH, @executables;
# Identical to the chmod 0755 of the example above.
+Portability issues: L<perlport/chmod>.
+
=item chomp VARIABLE
X<chomp> X<INPUT_RECORD_SEPARATOR> X<$/> X<newline> X<eol>
@@ -864,6 +874,8 @@ On POSIX systems, you can detect this condition this way:
use POSIX qw(sysconf _PC_CHOWN_RESTRICTED);
$can_chown_giveaway = not sysconf(_PC_CHOWN_RESTRICTED);
+Portability issues: L<perlport/chmod>.
+
=item chr NUMBER
X<chr> X<character> X<ASCII> X<Unicode>
@@ -898,6 +910,8 @@ change your current working directory, which is unaffected.) For security
reasons, this call is restricted to the superuser. If FILENAME is
omitted, does a C<chroot> to C<$_>.
+Portability issues: L<perlport/chroot>.
+
=item close FILEHANDLE
X<close>
@@ -1089,6 +1103,8 @@ the string back to an eight-bit byte string before calling crypt()
(on that copy). If that works, good. If not, crypt() dies with
C<Wide character in crypt>.
+Portability issues: L<perlport/crypt>.
+
=item dbmclose HASH
X<dbmclose>
@@ -1096,6 +1112,8 @@ X<dbmclose>
Breaks the binding between a DBM file and a hash.
+Portability issues: L<perlport/dbmclose>.
+
=item dbmopen HASH,DBNAME,MASK
X<dbmopen> X<dbm> X<ndbm> X<sdbm> X<gdbm>
@@ -1139,6 +1157,8 @@ before you call dbmopen():
dbmopen(%NS_Hist, "$ENV{HOME}/.netscape/history.db")
or die "Can't open netscape history file: $!";
+Portability issues: L<perlport/dbmopen>.
+
=item default BLOCK
Within a C<foreach> or a C<given>, a C<default> BLOCK acts like a C<when>
@@ -1475,6 +1495,8 @@ convert a core file into an executable. That's why you should now invoke
it as C<CORE::dump()>, if you don't want to be warned against a possible
typo.
+Portability issues: L<perlport/dump>.
+
=item each HASH
X<each> X<hash, iterator>
@@ -1802,6 +1824,8 @@ open handles to avoid lost output.
Note that C<exec> will not call your C<END> blocks, nor will it invoke
C<DESTROY> methods on your objects.
+Portability issues: L<perlport/exec>.
+
=item exists EXPR
X<exists> X<autovivification>
@@ -1896,6 +1920,8 @@ can change the exit status by modifying C<$?>. If this is a problem, you
can call C<POSIX:_exit($status)> to avoid END and destructor processing.
See L<perlmod> for details.
+Portability issues: L<perlport/exit>.
+
=item exp EXPR
X<exp> X<exponential> X<antilog> X<antilogarithm> X<e>
@@ -1941,6 +1967,8 @@ on your own, though.
$flags = fcntl(REMOTE, F_SETFL, $flags | O_NONBLOCK)
or die "Can't set flags for the socket: $!\n";
+Portability issues: L<perlport/fcntl>.
+
=item fileno FILEHANDLE
X<fileno>
@@ -2041,6 +2069,8 @@ function lose their locks, making it seriously harder to write servers.
See also L<DB_File> for other flock() examples.
+Portability issues: L<perlport/flock>.
+
=item fork
X<fork> X<child> X<parent>
@@ -2070,6 +2100,14 @@ if you exit, then the remote server (such as, say, a CGI script or a
backgrounded job launched from a remote shell) won't think you're done.
You should reopen those to F</dev/null> if it's any issue.
+On some platforms such as Windows, where the fork() system call is not available,
+Perl can be built to emulate fork() in the Perl interpreter. The emulation is designed to,
+at the level of the Perl program, be as compatible as possible with the "Unix" fork().
+However it has limitation that has to be considered in code intended to be portable.
+See L<perlfork> for more details.
+
+Portability issues: L<perlport/fork>.
+
=item format
X<format>
@@ -2161,6 +2199,8 @@ returns the empty string, use C<getpwuid>.
Do not consider C<getlogin> for authentication: it is not as
secure as C<getpwuid>.
+Portability issues: L<perlport/getlogin>.
+
=item getpeername SOCKET
X<getpeername> X<peer>
@@ -2183,6 +2223,8 @@ doesn't implement getpgrp(2). If PID is omitted, returns the process
group of the current process. Note that the POSIX version of C<getpgrp>
does not accept a PID argument, so only C<PID==0> is truly portable.
+Portability issues: L<perlport/getpgrp>.
+
=item getppid
X<getppid> X<parent> X<pid>
@@ -2195,6 +2237,8 @@ C<getppid()>, that returns a consistent value across threads. If you want
to call the underlying C<getppid()>, you may use the CPAN module
C<Linux::Pid>.
+Portability issues: L<perlport/getppid>.
+
=item getpriority WHICH,WHO
X<getpriority> X<priority> X<nice>
@@ -2202,6 +2246,8 @@ Returns the current priority for a process, a process group, or a user.
(See C<getpriority(2)>.) Will raise a fatal exception if used on a
machine that doesn't implement getpriority(2).
+Portability issues: L<perlport/getpriority>.
+
=item getpwnam NAME
X<getpwnam> X<getgrnam> X<gethostbyname> X<getnetbyname> X<getprotobyname>
X<getpwuid> X<getgrgid> X<getservbyname> X<gethostbyaddr> X<getnetbyaddr>
@@ -2373,6 +2419,8 @@ Even though it looks as though they're the same method calls (uid),
they aren't, because a C<File::stat> object is different from
a C<User::pwent> object.
+Portability issues: L<perlport/getpwnam> to L<perlport/endservent>.
+
=item getsockname SOCKET
X<getsockname>
@@ -2418,6 +2466,7 @@ Here's an example to test whether Nagle's algorithm is enabled on a socket:
my $nodelay = unpack("I", $packed);
print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";
+Portability issues: L<perlport/getsockopt>.
=item given EXPR BLOCK
X<given>
@@ -2472,6 +2521,8 @@ Beginning with v5.6.0, this operator is implemented using the standard
C<File::Glob> extension. See L<File::Glob> for details, including
C<bsd_glob> which does not treat whitespace as a pattern separator.
+Portability issues: L<perlport/glob>.
+
=item gmtime EXPR
X<gmtime> X<UTC> X<Greenwich>
@@ -2484,7 +2535,7 @@ Note: When called in list context, $isdst, the last value
returned by gmtime, is always C<0>. There is no
Daylight Saving Time in GMT.
-See L<perlport/gmtime> for portability concerns.
+Portability issues: L<perlport/gmtime>.
=item goto LABEL
X<goto> X<jump> X<jmp>
@@ -2661,6 +2712,8 @@ system:
The special string C<"0 but true"> is exempt from B<-w> complaints
about improper numeric conversions.
+Portability issues: L<perlport/ioctl>.
+
=item join EXPR,LIST
X<join>
@@ -2771,6 +2824,15 @@ signal the current process group and -1 will signal all processes.
See L<perlipc/"Signals"> for more details.
+On some platforms such as Windows where the fork() system call is not available.
+Perl can be built to emulate fork() at the interpreter level.
+This emulation has limitation related to kill that has to be considered,
+for code running on Windows and in code intended to be portable.
+
+See L<perlfork> for more details.
+
+Portability issues: L<perlport/kill>.
+
=item last LABEL
X<last> X<break>
@@ -2897,6 +2959,8 @@ X<link>
Creates a new filename linked to the old filename. Returns true for
success, false otherwise.
+Portability issues: L<perlport/link>.
+
=item listen SOCKET,QUEUESIZE
X<listen>
@@ -2990,8 +3054,6 @@ try for example:
Note that the C<%a> and C<%b>, the short forms of the day of the week
and the month of the year, may not necessarily be three characters wide.
-See L<perlport/localtime> for portability concerns.
-
The L<Time::gmtime> and L<Time::localtime> modules provide a convenient,
by-name access mechanism to the gmtime() and localtime() functions,
respectively.
@@ -2999,6 +3061,8 @@ respectively.
For a comprehensive date and time representation look at the
L<DateTime> module on CPAN.
+Portability issues: L<perlport/localtime>.
+
=item lock THING
X<lock>
@@ -3041,6 +3105,8 @@ information, please see the documentation for C<stat>.
If EXPR is omitted, stats C<$_>.
+Portability issues: L<perlport/lstat>.
+
=item m//
The match operator. See L<perlop/"Regexp Quote-Like Operators">.
@@ -3165,6 +3231,8 @@ C<"0 but true"> for zero, or the actual return value otherwise. See also
L<perlipc/"SysV IPC"> and the documentation for C<IPC::SysV> and
C<IPC::Semaphore>.
+Portability issues: L<perlport/msgctl>.
+
=item msgget KEY,FLAGS
X<msgget>
@@ -3173,6 +3241,8 @@ id, or C<undef> on error. See also
L<perlipc/"SysV IPC"> and the documentation for C<IPC::SysV> and
C<IPC::Msg>.
+Portability issues: L<perlport/msgget>.
+
=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
X<msgrcv>
@@ -3185,6 +3255,8 @@ Taints the variable. Returns true if successful, false
on error. See also L<perlipc/"SysV IPC"> and the documentation for
C<IPC::SysV> and C<IPC::SysV::Msg>.
+Portability issues: L<perlport/msgrcv>.
+
=item msgsnd ID,MSG,FLAGS
X<msgsnd>
@@ -3196,6 +3268,8 @@ C<pack("l! a*", $type, $message)>. Returns true if successful,
false on error. See also the C<IPC::SysV>
and C<IPC::SysV::Msg> documentation.
+Portability issues: L<perlport/msgsnd>.
+
=item my EXPR
X<my>
@@ -3705,6 +3779,8 @@ yourself and inspect the return value.
See L</seek> for some details about mixing reading and writing.
+Portability issues: L<perlport/open>.
+
=item opendir DIRHANDLE,EXPR
X<opendir>
@@ -4823,6 +4899,8 @@ implemented. If not, raises an exception. If there is a system
error, returns the undefined value and sets C<$!> (errno). If EXPR is
omitted, uses C<$_>.
+Portability issues: L<perlport/readlink>.
+
=item readpipe EXPR
=item readpipe
@@ -4956,6 +5034,8 @@ rename(2) manpage or equivalent system documentation for details.
For a platform independent C<move> function look at the L<File::Copy>
module.
+Portability issues: L<perlport/rename>.
+
=item require VERSION
X<require>
@@ -5216,6 +5296,8 @@ X<rewinddir>
Sets the current position to the beginning of the directory for the
C<readdir> routine on DIRHANDLE.
+Portability issues: L<perlport/rewinddir>.
+
=item rindex STR,SUBSTR,POSITION
X<rindex>
@@ -5374,6 +5456,8 @@ methods, preferring to write the last example as:
use IO::Handle;
STDERR->autoflush(1);
+Portability issues: L<perlport/select>.
+
=item select RBITS,WBITS,EBITS,TIMEOUT
X<select>
@@ -5438,6 +5522,8 @@ B<WARNING>: One should not attempt to mix buffered I/O (like C<read>
or <FH>) with C<select>, except as permitted by POSIX, and even
then only on POSIX systems. You have to use C<sysread> instead.
+Portability issues: L<perlport/select>.
+
=item semctl ID,SEMNUM,CMD,ARG
X<semctl>
@@ -5454,6 +5540,8 @@ short integers, which may be created with C<pack("s!",(0)x$nsem)>.
See also L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::Semaphore>
documentation.
+Portability issues: L<perlport/semctl>.
+
=item semget KEY,NSEMS,FLAGS
X<semget>
@@ -5462,6 +5550,8 @@ the undefined value on error. See also
L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::SysV::Semaphore>
documentation.
+Portability issues: L<perlport/semget>.
+
=item semop KEY,OPSTRING
X<semop>
@@ -5480,6 +5570,8 @@ To signal the semaphore, replace C<-1> with C<1>. See also
L<perlipc/"SysV IPC">, C<IPC::SysV>, and C<IPC::SysV::Semaphore>
documentation.
+Portability issues: L<perlport/semop>.
+
=item send SOCKET,MSG,FLAGS,TO
X<send>
@@ -5510,6 +5602,8 @@ it defaults to C<0,0>. Note that the BSD 4.2 version of C<setpgrp> does not
accept any arguments, so only C<setpgrp(0,0)> is portable. See also
C<POSIX::setsid()>.
+Portability issues: L<perlport/setpgrp>.
+
=item setpriority WHICH,WHO,PRIORITY
X<setpriority> X<priority> X<nice> X<renice>
@@ -5517,6 +5611,8 @@ Sets the current priority for a process, a process group, or a user.
(See setpriority(2).) Raises an exception when used on a machine
that doesn't implement setpriority(2).
+Portability issues: L<perlport/setpriority>.
+
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
X<setsockopt>
@@ -5531,6 +5627,8 @@ An example disabling Nagle's algorithm on a socket:
use Socket qw(IPPROTO_TCP TCP_NODELAY);
setsockopt($socket, IPPROTO_TCP, TCP_NODELAY, 1);
+Portability issues: L<perlport/setsockopt>.
+
=item shift ARRAY
X<shift>
@@ -5568,6 +5666,8 @@ structure. Returns like ioctl: C<undef> for error; "C<0> but
true" for zero; and the actual return value otherwise.
See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+Portability issues: L<perlport/shmctl>.
+
=item shmget KEY,SIZE,FLAGS
X<shmget>
@@ -5575,6 +5675,8 @@ Calls the System V IPC function shmget. Returns the shared memory
segment id, or C<undef> on error.
See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+Portability issues: L<perlport/shmget>.
+
=item shmread ID,VAR,POS,SIZE
X<shmread>
X<shmwrite>
@@ -5590,6 +5692,8 @@ SIZE bytes. Return true if successful, false on error.
shmread() taints the variable. See also L<perlipc/"SysV IPC">,
C<IPC::SysV>, and the C<IPC::Shareable> module from CPAN.
+Portability issues: L<perlport/shmread> and L<perlport/shmwrite>.
+
=item shutdown SOCKET,HOW
X<shutdown>
@@ -5694,6 +5798,8 @@ See L<perlipc> for an example of socketpair use. Perl 5.8 and later will
emulate socketpair using IP sockets to localhost if your system implements
sockets but not socketpair.
+Portability issues: L<perlport/socketpair>.
+
=item sort SUBNAME LIST
X<sort> X<qsort> X<quicksort> X<mergesort>
@@ -6602,6 +6708,8 @@ See your native chmod(2) and stat(2) documentation for more details
about the C<S_*> constants. To get status info for a symbolic link
instead of the target file behind the link, use the C<lstat> function.
+Portability issues: L<perlport/stat>.
+
=item state EXPR
X<state>
@@ -6771,6 +6879,8 @@ use eval:
$symlink_exists = eval { symlink("",""); 1 };
+Portability issues: L<perlport/symlink>.
+
=item syscall NUMBER, LIST
X<syscall> X<system call>
@@ -6806,6 +6916,8 @@ number of the read end of the pipe it creates, but there is no way
to retrieve the file number of the other end. You can avoid this
problem by using C<pipe> instead.
+Portability issues: L<perlport/syscall>.
+
=item sysopen FILEHANDLE,FILENAME,MODE
X<sysopen>
@@ -6869,6 +6981,8 @@ library, or perhaps using the POSIX::open() function.
See L<perlopentut> for a kinder, gentler explanation of opening files.
+Portability issues: L<perlport/sysopen>.
+
=item sysread FILEHANDLE,SCALAR,LENGTH,OFFSET
X<sysread>
@@ -7004,6 +7118,8 @@ See L<perlop/"`STRING`"> and L</exec> for details.
Since C<system> does a C<fork> and C<wait> it may affect a C<SIGCHLD>
handler. See L<perlipc> for details.
+Portability issues: L<perlport/system>.
+
=item syswrite FILEHANDLE,SCALAR,LENGTH,OFFSET
X<syswrite>
@@ -7198,6 +7314,8 @@ In scalar context, C<times> returns C<$user>.
Children's times are only included for terminated children.
+Portability issues: L<perlport/times>.
+
=item tr///
The transliteration operator. Same as C<y///>. See
@@ -7218,6 +7336,8 @@ file.
The position in the file of FILEHANDLE is left unchanged. You may want to
call L<seek|/"seek FILEHANDLE,POSITION,WHENCE"> before writing to the file.
+Portability issues: L<perlport/truncate>.
+
=item uc EXPR
X<uc> X<uppercase> X<toupper>
@@ -7285,6 +7405,8 @@ not trying to restrict access for yourself, returns C<undef>.
Remember that a umask is a number, usually given in octal; it is I<not> a
string of octal digits. See also L</oct>, if all you have is a string.
+Portability issues: L<perlport/umask>.
+
=item undef EXPR
X<undef> X<undefine>
@@ -7595,6 +7717,8 @@ files. On systems that don't support futimes(2), passing filehandles raises
an exception. Filehandles must be passed as globs or glob references to be
recognized; barewords are considered filenames.
+Portability issues: L<perlport/utime>.
+
=item values HASH
X<values>
@@ -7888,6 +8012,8 @@ being automatically reaped, as described in L<perlipc>.
If you use wait in your handler for $SIG{CHLD} it may accidentally for the
child created by qx() or system(). See L<perlipc> for details.
+Portability issues: L<perlport/wait>.
+
=item waitpid PID,FLAGS
X<waitpid>
@@ -7913,6 +8039,8 @@ Note that on some systems, a return value of C<-1> could mean that child
processes are being automatically reaped. See L<perlipc> for details,
and for other examples.
+Portability issues: L<perlport/waitpid>.
+
=item wantarray
X<wantarray> X<context>
--
1.7.3.1.msysgit.0
|
|
Bo.Johansson@lsn.se - Status changed from 'new' to 'open' |
|
Bo.Johansson@lsn.se - Status changed from 'open' to 'new' |
From @cpansproutOn Tue May 24 07:06:14 2011, boilund wrote:
I’m not sure it’s a good idea to add the reference to every entry in
perlfork already has this entry: =item kill() C<kill('KILL', ...)> can be used to terminate a pseudo-process by C<kill('TERM', ...)> can also be used on pseudo-processes, but the Does that not already cover this topic? |
|
The RT System itself - Status changed from 'new' to 'open' |
|
@cpansprout - Status changed from 'open' to 'rejected' |
From Bo.Johansson@lsn.seFather Chrysostomos, thank you for answering! First some BACKGROUND to the proposed patch. I have used Perl for more than 20 years, but I am quit new to installing Module Test-TCP: Module HTTP-Server-Simple: Module Plack: Perl function listen to socket: (The result of the bug reports are not overwhelming. Portability of test do One of my conclusions was that Perl does not provide enough support for I wrote the PerlMonks meditation: "Proposal how to make modules using fork
I am quit sure that the "small cost" to add some "cluttering" (What I also want is some sort of mark in the headline of functions with Non portable tests used in the test of modules are a problem. I have also found a type of portability problems which are difficult to find
I have used Perl in many years and have not observed the "item kill()". Concrete rules and recommendations what to do is needed. Some reasons why it is important to highlight the portability issues with - Kill are frequently used in Perl code. UNPREDICTABLE RESULT OF KILL ON PSEUDO-PROCESS Observations: 1) This always blocks in Windows 7, but not on Windows 2000: 2) This sometimes blocks and sometimes gives the wrong exit value 9 in 3) Running this batch file a number of times on Windows 7: @echo off gave the results: Perl is blocked after between 30 to several thousand loops. 4) The installations of module on Windows 7 using install in cpan frequently Conclusions and Implications: See also https://rt.cpan.org/Public/Bug/Display.html?id=66016#txn-910239. Best regards Bo Johansson |
|
@cpansprout - Status changed from 'rejected' to 'open' |
From @briandfoyIn article <rt-3.6.HEAD-16080-1306701350-570.91526-15-0@perl.org>,
If something has a portability issue, we should mention it in the main |
From @khwilliamsonOn 5/31/2011 1:33 PM, brian d foy wrote:
+1 |
From @janduboisOn Tue, 31 May 2011, brian d foy wrote:
Are you suggesting to fold the whole list of "FUNCTION IMPLEMENTATIONS" http://search.cpan.org/~jesse/perl-5.14.0/pod/perlport.pod#FUNCTION_IMPLEMENTATIONS Cheers, |
From Bo.Johansson@lsn.seThe proposal is (for functions with portability issues) to add a LINK -----Original Message----- On Tue, 31 May 2011, brian d foy wrote:
Are you suggesting to fold the whole list of "FUNCTION IMPLEMENTATIONS" http://search.cpan.org/~jesse/perl-5.14.0/pod/perlport.pod#FUNCTION_IMPLEMENTATIONS Cheers, |
From @cpansproutOn Mon May 30 19:51:51 2011, boilund wrote:
Fair enough. I tried applying your perlfunc patch, but it seems to have
I think it would be better to add something like this: =head1 PORTABILITY CAVEATS Killing a pseudo-process may have unpredictable results. See What do you think? If the existing kill() entry is not sufficient, would you be willing to |
From Bo.Johansson@lsn.se-----Original Message-----
Patch is attached as:
OK!
Proposal for changes to perlfork in the attached patch: |
From Bo.Johansson@lsn.se0001-Improve-documentation-to-support-portability.patchFrom 431c352c5f100131ab88c4e06acadbae490c115a Mon Sep 17 00:00:00 2001
From: bojilund <bo.johansso@lsn.se>
Date: Tue, 7 Jun 2011 09:32:31 +0200
Subject: [PATCH] Improve documentation to support portability
If something has a portability issue, we should mention it in the main
place people will read about the thing with the issue. For Perl
built-ins, that's perlfunc. We don't have to explain the issue, but we
should at the very least tell people where to find an explanation of
the issue.
---
pod/perlfunc.pod | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 131 insertions(+), 3 deletions(-)
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index e619424..53c8891 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -430,6 +430,8 @@ C<-x $file && -w _ && -f _>. (This is only fancy fancy: if you use
the return value of C<-f $file> as an argument to another filetest
operator, no special magic will happen.)
+Portability issues: L<perlport/x>.
+
=item abs VALUE
X<abs> X<absolute>
@@ -500,6 +502,8 @@ modulo the caveats given in L<perlipc/"Signals">.
For more information see L<perlipc>.
+Portability issues: L<perlport/alarm>.
+
=item atan2 Y,X
X<atan2> X<arctangent> X<tan> X<tangent>
@@ -513,6 +517,8 @@ function, or use the familiar relation:
The return value for C<atan2(0,0)> is implementation-defined; consult
your atan2(3) manpage for more information.
+Portability issues: L<perlport/atan2>.
+
=item bind SOCKET,NAME
X<bind>
@@ -612,6 +618,8 @@ but also when using read(), seek(), sysread(), syswrite() and tell()
in L<perlvar> for how to manually set your input and output
line-termination sequences.
+Portability issues: L<perlport/binmode>.
+
=item bless REF,CLASSNAME
X<bless>
@@ -761,6 +769,8 @@ module:
chmod S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH, @executables;
# Identical to the chmod 0755 of the example above.
+Portability issues: L<perlport/chmod>.
+
=item chomp VARIABLE
X<chomp> X<INPUT_RECORD_SEPARATOR> X<$/> X<newline> X<eol>
@@ -864,6 +874,8 @@ On POSIX systems, you can detect this condition this way:
use POSIX qw(sysconf _PC_CHOWN_RESTRICTED);
$can_chown_giveaway = not sysconf(_PC_CHOWN_RESTRICTED);
+Portability issues: L<perlport/chmod>.
+
=item chr NUMBER
X<chr> X<character> X<ASCII> X<Unicode>
@@ -898,6 +910,8 @@ change your current working directory, which is unaffected.) For security
reasons, this call is restricted to the superuser. If FILENAME is
omitted, does a C<chroot> to C<$_>.
+Portability issues: L<perlport/chroot>.
+
=item close FILEHANDLE
X<close>
@@ -1089,6 +1103,8 @@ the string back to an eight-bit byte string before calling crypt()
(on that copy). If that works, good. If not, crypt() dies with
C<Wide character in crypt>.
+Portability issues: L<perlport/crypt>.
+
=item dbmclose HASH
X<dbmclose>
@@ -1096,6 +1112,8 @@ X<dbmclose>
Breaks the binding between a DBM file and a hash.
+Portability issues: L<perlport/dbmclose>.
+
=item dbmopen HASH,DBNAME,MASK
X<dbmopen> X<dbm> X<ndbm> X<sdbm> X<gdbm>
@@ -1139,6 +1157,8 @@ before you call dbmopen():
dbmopen(%NS_Hist, "$ENV{HOME}/.netscape/history.db")
or die "Can't open netscape history file: $!";
+Portability issues: L<perlport/dbmopen>.
+
=item default BLOCK
Within a C<foreach> or a C<given>, a C<default> BLOCK acts like a C<when>
@@ -1475,6 +1495,8 @@ convert a core file into an executable. That's why you should now invoke
it as C<CORE::dump()>, if you don't want to be warned against a possible
typo.
+Portability issues: L<perlport/dump>.
+
=item each HASH
X<each> X<hash, iterator>
@@ -1805,6 +1827,8 @@ open handles to avoid lost output.
Note that C<exec> will not call your C<END> blocks, nor will it invoke
C<DESTROY> methods on your objects.
+Portability issues: L<perlport/exec>.
+
=item exists EXPR
X<exists> X<autovivification>
@@ -1899,6 +1923,8 @@ can change the exit status by modifying C<$?>. If this is a problem, you
can call C<POSIX:_exit($status)> to avoid END and destructor processing.
See L<perlmod> for details.
+Portability issues: L<perlport/exit>.
+
=item exp EXPR
X<exp> X<exponential> X<antilog> X<antilogarithm> X<e>
@@ -1944,6 +1970,8 @@ on your own, though.
$flags = fcntl(REMOTE, F_SETFL, $flags | O_NONBLOCK)
or die "Can't set flags for the socket: $!\n";
+Portability issues: L<perlport/fcntl>.
+
=item fileno FILEHANDLE
X<fileno>
@@ -2044,6 +2072,8 @@ function lose their locks, making it seriously harder to write servers.
See also L<DB_File> for other flock() examples.
+Portability issues: L<perlport/flock>.
+
=item fork
X<fork> X<child> X<parent>
@@ -2073,6 +2103,14 @@ if you exit, then the remote server (such as, say, a CGI script or a
backgrounded job launched from a remote shell) won't think you're done.
You should reopen those to F</dev/null> if it's any issue.
+On some platforms such as Windows, where the fork() system call is not available,
+Perl can be built to emulate fork() in the Perl interpreter. The emulation is designed to,
+at the level of the Perl program, be as compatible as possible with the "Unix" fork().
+However it has limitation that has to be considered in code intended to be portable.
+See L<perlfork> for more details.
+
+Portability issues: L<perlport/fork>.
+
=item format
X<format>
@@ -2164,6 +2202,8 @@ returns the empty string, use C<getpwuid>.
Do not consider C<getlogin> for authentication: it is not as
secure as C<getpwuid>.
+Portability issues: L<perlport/getlogin>.
+
=item getpeername SOCKET
X<getpeername> X<peer>
@@ -2186,6 +2226,8 @@ doesn't implement getpgrp(2). If PID is omitted, returns the process
group of the current process. Note that the POSIX version of C<getpgrp>
does not accept a PID argument, so only C<PID==0> is truly portable.
+Portability issues: L<perlport/getpgrp>.
+
=item getppid
X<getppid> X<parent> X<pid>
@@ -2198,6 +2240,8 @@ C<getppid()>, that returns a consistent value across threads. If you want
to call the underlying C<getppid()>, you may use the CPAN module
C<Linux::Pid>.
+Portability issues: L<perlport/getppid>.
+
=item getpriority WHICH,WHO
X<getpriority> X<priority> X<nice>
@@ -2205,6 +2249,8 @@ Returns the current priority for a process, a process group, or a user.
(See C<getpriority(2)>.) Will raise a fatal exception if used on a
machine that doesn't implement getpriority(2).
+Portability issues: L<perlport/getpriority>.
+
=item getpwnam NAME
X<getpwnam> X<getgrnam> X<gethostbyname> X<getnetbyname> X<getprotobyname>
X<getpwuid> X<getgrgid> X<getservbyname> X<gethostbyaddr> X<getnetbyaddr>
@@ -2376,6 +2422,8 @@ Even though it looks as though they're the same method calls (uid),
they aren't, because a C<File::stat> object is different from
a C<User::pwent> object.
+Portability issues: L<perlport/getpwnam> to L<perlport/endservent>.
+
=item getsockname SOCKET
X<getsockname>
@@ -2421,6 +2469,7 @@ Here's an example to test whether Nagle's algorithm is enabled on a socket:
my $nodelay = unpack("I", $packed);
print "Nagle's algorithm is turned ", $nodelay ? "off\n" : "on\n";
+Portability issues: L<perlport/getsockopt>.
=item given EXPR BLOCK
X<given>
@@ -2475,6 +2524,8 @@ Beginning with v5.6.0, this operator is implemented using the standard
C<File::Glob> extension. See L<File::Glob> for details, including
C<bsd_glob> which does not treat whitespace as a pattern separator.
+Portability issues: L<perlport/glob>.
+
=item gmtime EXPR
X<gmtime> X<UTC> X<Greenwich>
@@ -2487,7 +2538,7 @@ Note: When called in list context, $isdst, the last value
returned by gmtime, is always C<0>. There is no
Daylight Saving Time in GMT.
-See L<perlport/gmtime> for portability concerns.
+Portability issues: L<perlport/gmtime>.
=item goto LABEL
X<goto> X<jump> X<jmp>
@@ -2664,6 +2715,8 @@ system:
The special string C<"0 but true"> is exempt from B<-w> complaints
about improper numeric conversions.
+Portability issues: L<perlport/ioctl>.
+
=item join EXPR,LIST
X<join>
@@ -2774,6 +2827,15 @@ signal the current process group and -1 will signal all processes.
See L<perlipc/"Signals"> for more details.
+On some platforms such as Windows where the fork() system call is not available.
+Perl can be built to emulate fork() at the interpreter level.
+This emulation has limitation related to kill that has to be considered,
+for code running on Windows and in code intended to be portable.
+
+See L<perlfork> for more details.
+
+Portability issues: L<perlport/kill>.
+
=item last LABEL
X<last> X<break>
@@ -2900,6 +2962,8 @@ X<link>
Creates a new filename linked to the old filename. Returns true for
success, false otherwise.
+Portability issues: L<perlport/link>.
+
=item listen SOCKET,QUEUESIZE
X<listen>
@@ -2993,8 +3057,6 @@ try for example:
Note that the C<%a> and C<%b>, the short forms of the day of the week
and the month of the year, may not necessarily be three characters wide.
-See L<perlport/localtime> for portability concerns.
-
The L<Time::gmtime> and L<Time::localtime> modules provide a convenient,
by-name access mechanism to the gmtime() and localtime() functions,
respectively.
@@ -3002,6 +3064,8 @@ respectively.
For a comprehensive date and time representation look at the
L<DateTime> module on CPAN.
+Portability issues: L<perlport/localtime>.
+
=item lock THING
X<lock>
@@ -3044,6 +3108,8 @@ information, please see the documentation for C<stat>.
If EXPR is omitted, stats C<$_>.
+Portability issues: L<perlport/lstat>.
+
=item m//
The match operator. See L<perlop/"Regexp Quote-Like Operators">.
@@ -3168,6 +3234,8 @@ C<"0 but true"> for zero, or the actual return value otherwise. See also
L<perlipc/"SysV IPC"> and the documentation for C<IPC::SysV> and
C<IPC::Semaphore>.
+Portability issues: L<perlport/msgctl>.
+
=item msgget KEY,FLAGS
X<msgget>
@@ -3176,6 +3244,8 @@ id, or C<undef> on error. See also
L<perlipc/"SysV IPC"> and the documentation for C<IPC::SysV> and
C<IPC::Msg>.
+Portability issues: L<perlport/msgget>.
+
=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
X<msgrcv>
@@ -3188,6 +3258,8 @@ Taints the variable. Returns true if successful, false
on error. See also L<perlipc/"SysV IPC"> and the documentation for
C<IPC::SysV> and C<IPC::SysV::Msg>.
+Portability issues: L<perlport/msgrcv>.
+
=item msgsnd ID,MSG,FLAGS
X<msgsnd>
@@ -3199,6 +3271,8 @@ C<pack("l! a*", $type, $message)>. Returns true if successful,
false on error. See also the C<IPC::SysV>
and C<IPC::SysV::Msg> documentation.
+Portability issues: L<perlport/msgsnd>.
+
=item my EXPR
X<my>
@@ -3708,6 +3782,8 @@ yourself and inspect the return value.
See L</seek> for some details about mixing reading and writing.
+Portability issues: L<perlport/open>.
+
=item opendir DIRHANDLE,EXPR
X<opendir>
@@ -4826,6 +4902,8 @@ implemented. If not, raises an exception. If there is a system
error, returns the undefined value and sets C<$!> (errno). If EXPR is
omitted, uses C<$_>.
+Portability issues: L<perlport/readlink>.
+
=item readpipe EXPR
=item readpipe
@@ -4959,6 +5037,8 @@ rename(2) manpage or equivalent system documentation for details.
For a platform independent C<move> function look at the L<File::Copy>
module.
+Portability issues: L<perlport/rename>.
+
=item require VERSION
X<require>
@@ -5219,6 +5299,8 @@ X<rewinddir>
Sets the current position to the beginning of the directory for the
C<readdir> routine on DIRHANDLE.
+Portability issues: L<perlport/rewinddir>.
+
=item rindex STR,SUBSTR,POSITION
X<rindex>
@@ -5377,6 +5459,8 @@ methods, preferring to write the last example as:
use IO::Handle;
STDERR->autoflush(1);
+Portability issues: L<perlport/select>.
+
=item select RBITS,WBITS,EBITS,TIMEOUT
X<select>
@@ -5441,6 +5525,8 @@ B<WARNING>: One should not attempt to mix buffered I/O (like C<read>
or <FH>) with C<select>, except as permitted by POSIX, and even
then only on POSIX systems. You have to use C<sysread> instead.
+Portability issues: L<perlport/select>.
+
=item semctl ID,SEMNUM,CMD,ARG
X<semctl>
@@ -5457,6 +5543,8 @@ short integers, which may be created with C<pack("s!",(0)x$nsem)>.
See also L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::Semaphore>
documentation.
+Portability issues: L<perlport/semctl>.
+
=item semget KEY,NSEMS,FLAGS
X<semget>
@@ -5465,6 +5553,8 @@ the undefined value on error. See also
L<perlipc/"SysV IPC">, C<IPC::SysV>, C<IPC::SysV::Semaphore>
documentation.
+Portability issues: L<perlport/semget>.
+
=item semop KEY,OPSTRING
X<semop>
@@ -5483,6 +5573,8 @@ To signal the semaphore, replace C<-1> with C<1>. See also
L<perlipc/"SysV IPC">, C<IPC::SysV>, and C<IPC::SysV::Semaphore>
documentation.
+Portability issues: L<perlport/semop>.
+
=item send SOCKET,MSG,FLAGS,TO
X<send>
@@ -5513,6 +5605,8 @@ it defaults to C<0,0>. Note that the BSD 4.2 version of C<setpgrp> does not
accept any arguments, so only C<setpgrp(0,0)> is portable. See also
C<POSIX::setsid()>.
+Portability issues: L<perlport/setpgrp>.
+
=item setpriority WHICH,WHO,PRIORITY
X<setpriority> X<priority> X<nice> X<renice>
@@ -5520,6 +5614,8 @@ Sets the current priority for a process, a process group, or a user.
(See setpriority(2).) Raises an exception when used on a machine
that doesn't implement setpriority(2).
+Portability issues: L<perlport/setpriority>.
+
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
X<setsockopt>
@@ -5534,6 +5630,8 @@ An example disabling Nagle's algorithm on a socket:
use Socket qw(IPPROTO_TCP TCP_NODELAY);
setsockopt($socket, IPPROTO_TCP, TCP_NODELAY, 1);
+Portability issues: L<perlport/setsockopt>.
+
=item shift ARRAY
X<shift>
@@ -5571,6 +5669,8 @@ structure. Returns like ioctl: C<undef> for error; "C<0> but
true" for zero; and the actual return value otherwise.
See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+Portability issues: L<perlport/shmctl>.
+
=item shmget KEY,SIZE,FLAGS
X<shmget>
@@ -5578,6 +5678,8 @@ Calls the System V IPC function shmget. Returns the shared memory
segment id, or C<undef> on error.
See also L<perlipc/"SysV IPC"> and C<IPC::SysV> documentation.
+Portability issues: L<perlport/shmget>.
+
=item shmread ID,VAR,POS,SIZE
X<shmread>
X<shmwrite>
@@ -5593,6 +5695,8 @@ SIZE bytes. Return true if successful, false on error.
shmread() taints the variable. See also L<perlipc/"SysV IPC">,
C<IPC::SysV>, and the C<IPC::Shareable> module from CPAN.
+Portability issues: L<perlport/shmread> and L<perlport/shmwrite>.
+
=item shutdown SOCKET,HOW
X<shutdown>
@@ -5697,6 +5801,8 @@ See L<perlipc> for an example of socketpair use. Perl 5.8 and later will
emulate socketpair using IP sockets to localhost if your system implements
sockets but not socketpair.
+Portability issues: L<perlport/socketpair>.
+
=item sort SUBNAME LIST
X<sort> X<qsort> X<quicksort> X<mergesort>
@@ -6605,6 +6711,8 @@ See your native chmod(2) and stat(2) documentation for more details
about the C<S_*> constants. To get status info for a symbolic link
instead of the target file behind the link, use the C<lstat> function.
+Portability issues: L<perlport/stat>.
+
=item state EXPR
X<state>
@@ -6774,6 +6882,8 @@ use eval:
$symlink_exists = eval { symlink("",""); 1 };
+Portability issues: L<perlport/symlink>.
+
=item syscall NUMBER, LIST
X<syscall> X<system call>
@@ -6809,6 +6919,8 @@ number of the read end of the pipe it creates, but there is no way
to retrieve the file number of the other end. You can avoid this
problem by using C<pipe> instead.
+Portability issues: L<perlport/syscall>.
+
=item sysopen FILEHANDLE,FILENAME,MODE
X<sysopen>
@@ -6872,6 +6984,8 @@ library, or perhaps using the POSIX::open() function.
See L<perlopentut> for a kinder, gentler explanation of opening files.
+Portability issues: L<perlport/sysopen>.
+
=item sysread FILEHANDLE,SCALAR,LENGTH,OFFSET
X<sysread>
@@ -7007,6 +7121,8 @@ See L<perlop/"`STRING`"> and L</exec> for details.
Since C<system> does a C<fork> and C<wait> it may affect a C<SIGCHLD>
handler. See L<perlipc> for details.
+Portability issues: L<perlport/system>.
+
=item syswrite FILEHANDLE,SCALAR,LENGTH,OFFSET
X<syswrite>
@@ -7201,6 +7317,8 @@ In scalar context, C<times> returns C<$user>.
Children's times are only included for terminated children.
+Portability issues: L<perlport/times>.
+
=item tr///
The transliteration operator. Same as C<y///>. See
@@ -7221,6 +7339,8 @@ file.
The position in the file of FILEHANDLE is left unchanged. You may want to
call L<seek|/"seek FILEHANDLE,POSITION,WHENCE"> before writing to the file.
+Portability issues: L<perlport/truncate>.
+
=item uc EXPR
X<uc> X<uppercase> X<toupper>
@@ -7288,6 +7408,8 @@ not trying to restrict access for yourself, returns C<undef>.
Remember that a umask is a number, usually given in octal; it is I<not> a
string of octal digits. See also L</oct>, if all you have is a string.
+Portability issues: L<perlport/umask>.
+
=item undef EXPR
X<undef> X<undefine>
@@ -7598,6 +7720,8 @@ files. On systems that don't support futimes(2), passing filehandles raises
an exception. Filehandles must be passed as globs or glob references to be
recognized; barewords are considered filenames.
+Portability issues: L<perlport/utime>.
+
=item values HASH
X<values>
@@ -7891,6 +8015,8 @@ being automatically reaped, as described in L<perlipc>.
If you use wait in your handler for $SIG{CHLD} it may accidentally for the
child created by qx() or system(). See L<perlipc> for details.
+Portability issues: L<perlport/wait>.
+
=item waitpid PID,FLAGS
X<waitpid>
@@ -7916,6 +8042,8 @@ Note that on some systems, a return value of C<-1> could mean that child
processes are being automatically reaped. See L<perlipc> for details,
and for other examples.
+Portability issues: L<perlport/waitpid>.
+
=item wantarray
X<wantarray> X<context>
--
1.7.3.1.msysgit.0
|
From Bo.Johansson@lsn.se0001-Add-information-about-portability-caveats-related-to.patchFrom f20405c643e7886ae013baee00bf2763ad65bc1d Mon Sep 17 00:00:00 2001
From: bojilund <bo.johansso@lsn.se>
Date: Tue, 7 Jun 2011 10:24:43 +0200
Subject: [PATCH] Add information about portability caveats related to using kill on forked process.
The outcome of kill on a pseudo-process in Windows is unpredictable
and it should not be used except under dire circumstances.
The process which implements the pseudo-processes can be blocked
and the Perl interpreter hangs.
---
pod/perlfork.pod | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/pod/perlfork.pod b/pod/perlfork.pod
index 709d053..4257b87 100644
--- a/pod/perlfork.pod
+++ b/pod/perlfork.pod
@@ -78,10 +78,12 @@ and return its status.
=item kill()
C<kill('KILL', ...)> can be used to terminate a pseudo-process by
-passing it the ID returned by fork(). This should not be used except
+passing it the ID returned by fork(). The outcome of kill on a pseudo-process
+is unpredictable and it should not be used except
under dire circumstances, because the operating system may not
guarantee integrity of the process resources when a running thread is
-terminated. Note that using C<kill('KILL', ...)> on a
+terminated. The process which implements the pseudo-processes can be blocked
+and the Perl interpreter hangs. Note that using C<kill('KILL', ...)> on a
pseudo-process() may typically cause memory leaks, because the thread
that implements the pseudo-process does not get a chance to clean up
its resources.
@@ -307,6 +309,12 @@ are expected to be fixed for thread-safety.
=back
+=head1 PORTABILITY CAVEATS
+
+In portable Perl code, C<kill(9, $child)> must not be used on forked processes.
+Killing a forked process is unsafe and have unpredictable results.
+See L</kill()>, above.
+
=head1 BUGS
=over 8
--
1.7.3.1.msysgit.0
|
From @cpansproutOn Tue Jun 07 01:44:40 2011, boilund wrote:
Thank you. I’ve applied those as commits ea9eb35 and bd1171b. |
|
@cpansprout - Status changed from 'open' to 'resolved' |
Migrated from rt.perl.org#91526 (status was 'resolved')
Searchable as RT91526$
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