perl5004delta.1

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

additions also make it feasible to manipulate \f(CW\*(C`HE*\*(C'\fRs (hash entries),
which can be more efficient.  See perlguts for details.
.SH "Documentation Changes"
.IX Header "Documentation Changes"
Many of the base and library pods were updated.  These
new pods are included in section 1:
.IP "perldelta" 4
.IX Item "perldelta"
This document.
.IP "perlfaq" 4
.IX Item "perlfaq"
Frequently asked questions.
.IP "perllocale" 4
.IX Item "perllocale"
Locale support (internationalization and localization).
.IP "perltoot" 4
.IX Item "perltoot"
Tutorial on Perl \s-1OO\s0 programming.
.IP "perlapio" 4
.IX Item "perlapio"
Perl internal \s-1IO\s0 abstraction interface.
.IP "perlmodlib" 4
.IX Item "perlmodlib"
Perl module library and recommended practice for module creation.
Extracted from perlmod (which is much smaller as a result).
.IP "perldebug" 4
.IX Item "perldebug"
Although not new, this has been massively updated.
.IP "perlsec" 4
.IX Item "perlsec"
Although not new, this has been massively updated.
.SH "New Diagnostics"
.IX Header "New Diagnostics"
Several new conditions will trigger warnings that were
silent before.  Some only affect certain platforms.
The following new warnings and errors outline these.
These messages are classified as follows (listed in
increasing order of desperation):
.PP
.Vb 7
\&   (W) A warning (optional).
\&   (D) A deprecation (optional).
\&   (S) A severe warning (mandatory).
\&   (F) A fatal error (trappable).
\&   (P) An internal error you should never see (trappable).
\&   (X) A very fatal error (nontrappable).
\&   (A) An alien error message (not generated by Perl).
.Ve
.ie n .IP """my"" variable %s masks earlier declaration in same scope" 4
.el .IP "``my'' variable \f(CW%s\fR masks earlier declaration in same scope" 4
.IX Item "my variable %s masks earlier declaration in same scope"
(W) A lexical variable has been redeclared in the same scope, effectively
eliminating all access to the previous instance.  This is almost always
a typographical error.  Note that the earlier variable will still exist
until the end of the scope or until all closure referents to it are
destroyed.
.ie n .IP "%s argument is not a \s-1HASH\s0 element or slice" 4
.el .IP "\f(CW%s\fR argument is not a \s-1HASH\s0 element or slice" 4
.IX Item "%s argument is not a HASH element or slice"
(F) The argument to \fIdelete()\fR must be either a hash element, such as
.Sp
.Vb 2
\&    $foo{$bar}
\&    $ref\->[12]\->{"susie"}
.Ve
.Sp
or a hash slice, such as
.Sp
.Vb 2
\&    @foo{$bar, $baz, $xyzzy}
\&    @{$ref\->[12]}{"susie", "queue"}
.Ve
.ie n .IP "Allocation too large: %lx" 4
.el .IP "Allocation too large: \f(CW%lx\fR" 4
.IX Item "Allocation too large: %lx"
(X) You can't allocate more than 64K on an MS-DOS machine.
.IP "Allocation too large" 4
.IX Item "Allocation too large"
(F) You can't allocate more than 2^31+\*(L"small amount\*(R" bytes.
.ie n .IP "Applying %s\fR to \f(CW%s will act on scalar(%s)" 4
.el .IP "Applying \f(CW%s\fR to \f(CW%s\fR will act on scalar(%s)" 4
.IX Item "Applying %s to %s will act on scalar(%s)"
(W) The pattern match (//), substitution (s///), and transliteration (tr///)
operators work on scalar values.  If you apply one of them to an array
or a hash, it will convert the array or hash to a scalar value \*(-- the
length of an array, or the population info of a hash \*(-- and then work on
that scalar value.  This is probably not what you meant to do.  See
\&\*(L"grep\*(R" in perlfunc and \*(L"map\*(R" in perlfunc for alternatives.
.IP "Attempt to free nonexistent shared string" 4
.IX Item "Attempt to free nonexistent shared string"
(P) Perl maintains a reference counted internal table of strings to
optimize the storage and access of hash keys and other strings.  This
indicates someone tried to decrement the reference count of a string
that can no longer be found in the table.
.IP "Attempt to use reference as lvalue in substr" 4
.IX Item "Attempt to use reference as lvalue in substr"
(W) You supplied a reference as the first argument to \fIsubstr()\fR used
as an lvalue, which is pretty strange.  Perhaps you forgot to
dereference it first.  See \*(L"substr\*(R" in perlfunc.
.ie n .IP "Bareword ""%s"" refers to nonexistent package" 4
.el .IP "Bareword ``%s'' refers to nonexistent package" 4
.IX Item "Bareword %s refers to nonexistent package"
(W) You used a qualified bareword of the form \f(CW\*(C`Foo::\*(C'\fR, but
the compiler saw no other uses of that namespace before that point.
Perhaps you need to predeclare a package?
.ie n .IP "Can't redefine active sort subroutine %s" 4
.el .IP "Can't redefine active sort subroutine \f(CW%s\fR" 4
.IX Item "Can't redefine active sort subroutine %s"
(F) Perl optimizes the internal handling of sort subroutines and keeps
pointers into them.  You tried to redefine one such sort subroutine when it
was currently active, which is not allowed.  If you really want to do
this, you should write \f(CW\*(C`sort { &func } @x\*(C'\fR instead of \f(CW\*(C`sort func @x\*(C'\fR.
.ie n .IP "Can't use bareword (""%s"") as %s ref while ""strict refs"" in use" 4
.el .IP "Can't use bareword (``%s'') as \f(CW%s\fR ref while ``strict refs'' in use" 4
.IX Item "Can't use bareword (%s) as %s ref while strict refs in use"
(F) Only hard references are allowed by \*(L"strict refs\*(R".  Symbolic references
are disallowed.  See perlref.
.IP "Cannot resolve method `%s' overloading `%s' in package `%s'" 4
.IX Item "Cannot resolve method `%s' overloading `%s' in package `%s'"
(P) Internal error trying to resolve overloading specified by a method
name (as opposed to a subroutine reference).
.ie n .IP "Constant subroutine %s redefined" 4
.el .IP "Constant subroutine \f(CW%s\fR redefined" 4
.IX Item "Constant subroutine %s redefined"
(S) You redefined a subroutine which had previously been eligible for
inlining.  See \*(L"Constant Functions\*(R" in perlsub for commentary and
workarounds.
.ie n .IP "Constant subroutine %s undefined" 4
.el .IP "Constant subroutine \f(CW%s\fR undefined" 4
.IX Item "Constant subroutine %s undefined"
(S) You undefined a subroutine which had previously been eligible for
inlining.  See \*(L"Constant Functions\*(R" in perlsub for commentary and
workarounds.
.IP "Copy method did not return a reference" 4
.IX Item "Copy method did not return a reference"
(F) The method which overloads \*(L"=\*(R" is buggy. See \*(L"Copy Constructor\*(R" in overload.
.IP "Died" 4
.IX Item "Died"
(F) You passed \fIdie()\fR an empty string (the equivalent of \f(CW\*(C`die ""\*(C'\fR) or
you called it with no args and both \f(CW$@\fR and \f(CW$_\fR were empty.
.ie n .IP "Exiting pseudo-block via %s" 4
.el .IP "Exiting pseudo-block via \f(CW%s\fR" 4
.IX Item "Exiting pseudo-block via %s"
(W) You are exiting a rather special block construct (like a sort block or
subroutine) by unconventional means, such as a goto, or a loop control
statement.  See \*(L"sort\*(R" in perlfunc.
.IP "Identifier too long" 4
.IX Item "Identifier too long"
(F) Perl limits identifiers (names for variables, functions, etc.) to
252 characters for simple names, somewhat more for compound names (like
\&\f(CW$A::B\fR).  You've exceeded Perl's limits.  Future versions of Perl are
likely to eliminate these arbitrary limitations.
.ie n .IP "Illegal character %s (carriage return)" 4
.el .IP "Illegal character \f(CW%s\fR (carriage return)" 4
.IX Item "Illegal character %s (carriage return)"
(F) A carriage return character was found in the input.  This is an
error, and not a warning, because carriage return characters can break
multi-line strings, including here documents (e.g., \f(CW\*(C`print <<EOF;\*(C'\fR).
.ie n .IP "Illegal switch in \s-1PERL5OPT:\s0 %s" 4
.el .IP "Illegal switch in \s-1PERL5OPT:\s0 \f(CW%s\fR" 4
.IX Item "Illegal switch in PERL5OPT: %s"
(X) The \s-1PERL5OPT\s0 environment variable may only be used to set the
following switches: \fB\-[DIMUdmw]\fR.
.IP "Integer overflow in hex number" 4
.IX Item "Integer overflow in hex number"
(S) The literal hex number you have specified is too big for your
architecture. On a 32\-bit architecture the largest hex literal is
0xFFFFFFFF.
.IP "Integer overflow in octal number" 4
.IX Item "Integer overflow in octal number"
(S) The literal octal number you have specified is too big for your
architecture. On a 32\-bit architecture the largest octal literal is
037777777777.
.IP "internal error: glob failed" 4
.IX Item "internal error: glob failed"
(P) Something went wrong with the external program(s) used for \f(CW\*(C`glob\*(C'\fR
and \f(CW\*(C`<*.c>\*(C'\fR.  This may mean that your csh (C shell) is
broken.  If so, you should change all of the csh-related variables in
config.sh:  If you have tcsh, make the variables refer to it as if it
were csh (e.g. \f(CW\*(C`full_csh=\*(Aq/usr/bin/tcsh\*(Aq\*(C'\fR); otherwise, make them all
empty (except that \f(CW\*(C`d_csh\*(C'\fR should be \f(CW\*(Aqundef\*(Aq\fR) so that Perl will
think csh is missing.  In either case, after editing config.sh, run
\&\f(CW\*(C`./Configure \-S\*(C'\fR and rebuild Perl.
.ie n .IP "Invalid conversion in %s: ""%s""" 4
.el .IP "Invalid conversion in \f(CW%s:\fR ``%s''" 4
.IX Item "Invalid conversion in %s: %s"
(W) Perl does not understand the given format conversion.
See \*(L"sprintf\*(R" in perlfunc.
.IP "Invalid type in pack: '%s'" 4
.IX Item "Invalid type in pack: '%s'"
(F) The given character is not a valid pack type.  See \*(L"pack\*(R" in perlfunc.
.IP "Invalid type in unpack: '%s'" 4
.IX Item "Invalid type in unpack: '%s'"
(F) The given character is not a valid unpack type.  See \*(L"unpack\*(R" in perlfunc.
.ie n .IP "Name ""%s::%s"" used only once: possible typo" 4
.el .IP "Name ``%s::%s'' used only once: possible typo" 4
.IX Item "Name %s::%s used only once: possible typo"
(W) Typographical errors often show up as unique variable names.
If you had a good reason for having a unique name, then just mention
it again somehow to suppress the message (the \f(CW\*(C`use vars\*(C'\fR pragma is
provided for just this purpose).
.IP "Null picture in formline" 4
.IX Item "Null picture in formline"
(F) The first argument to formline must be a valid format picture
specification.  It was found to be empty, which probably means you
supplied it an uninitialized value.  See perlform.
.IP "Offset outside string" 4
.IX Item "Offset outside string"
(F) You tried to do a read/write/send/recv operation with an offset
pointing outside the buffer.  This is difficult to imagine.
The sole exception to this is that \f(CW\*(C`sysread()\*(C'\fRing past the buffer
will extend the buffer and zero pad the new area.
.IP "Out of memory!" 4
.IX Item "Out of memory!"
(X|F) The \fImalloc()\fR function returned 0, indicating there was insufficient
remaining memory (or virtual memory) to satisfy the request.
.Sp
The request was judged to be small, so the possibility to trap it
depends on the way Perl was compiled.  By default it is not trappable.
However, if compiled for this, Perl may use the contents of \f(CW$^M\fR as
an emergency pool after \fIdie()\fRing with this message.  In this case the
error is trappable \fIonce\fR.
.ie n .IP "Out of memory during request for %s" 4
.el .IP "Out of memory during request for \f(CW%s\fR" 4
.IX Item "Out of memory during request for %s"
(F) The \fImalloc()\fR function returned 0, indicating there was insufficient
remaining memory (or virtual memory) to satisfy the request. However,
the request was judged large enough (compile-time default is 64K), so
a possibility to shut down by trapping this error is granted.
.IP "panic: frexp" 4
.IX Item "panic: frexp"
(P) The library function \fIfrexp()\fR failed, making printf(\*(L"%f\*(R") impossible.
.IP "Possible attempt to put comments in \fIqw()\fR list" 4
.IX Item "Possible attempt to put comments in qw() list"
(W) \fIqw()\fR lists contain items separated by whitespace; as with literal
strings, comment characters are not ignored, but are instead treated
as literal data.  (You may have used different delimiters than the
parentheses shown here; braces are also frequently used.)
.Sp
You probably wrote something like this:
.Sp
.Vb 4
\&    @list = qw(
\&        a # a comment
\&        b # another comment
\&    );
.Ve
.Sp
when you should have written this:
.Sp
.Vb 4
\&    @list = qw(
\&        a
\&        b
\&    );
.Ve
.Sp
If you really want comments, build your list the
old-fashioned way, with quotes and commas:
.Sp
.Vb 4
\&    @list = (
\&        \*(Aqa\*(Aq,    # a comment
\&        \*(Aqb\*(Aq,    # another comment
\&    );
.Ve
.IP "Possible attempt to separate words with commas" 4
.IX Item "Possible attempt to separate words with commas"
(W) \fIqw()\fR lists contain items separated by whitespace; therefore commas
aren't needed to separate the items. (You may have used different
delimiters than the parentheses shown here; braces are also frequently
used.)
.Sp
You probably wrote something like this:
.Sp
.Vb 1
\&    qw! a, b, c !;
.Ve
.Sp
which puts literal commas into some of the list items.  Write it without
commas if you don't want them to appear in your data:
.Sp
.Vb 1
\&    qw! a b c !;
.Ve
.IP "Scalar value @%s{%s} better written as $%s{%s}" 4
.IX Item "Scalar value @%s{%s} better written as $%s{%s}"
(W) You've used a hash slice (indicated by @) to select a single element of
a hash.  Generally it's better to ask for a scalar value (indicated by $).
The difference is that \f(CW$foo{&bar}\fR always behaves like a scalar, both when
assigning to it and when evaluating its argument, while \f(CW@foo{&bar}\fR behaves
like a list when you assign to it, and provides a li