--- /dev/null
+.\" Automatically generated by Pod::Man 2.22 (Pod::Simple 3.10)
+.\"
+.\" Standard preamble:
+.\" ========================================================================
+.de Sp \" Vertical space (when we can't use .PP)
+.if t .sp .5v
+.if n .sp
+..
+.de Vb \" Begin verbatim text
+.ft CW
+.nf
+.ne \\$1
+..
+.de Ve \" End verbatim text
+.ft R
+.fi
+..
+.\" Set up some character translations and predefined strings. \*(-- will
+.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
+.\" double quote, and \*(R" will give a right double quote. \*(C+ will
+.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
+.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
+.\" nothing in troff, for use with C<>.
+.tr \(*W-
+.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
+.ie n \{\
+. ds -- \(*W-
+. ds PI pi
+. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
+. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
+. ds L" ""
+. ds R" ""
+. ds C` ""
+. ds C' ""
+'br\}
+.el\{\
+. ds -- \|\(em\|
+. ds PI \(*p
+. ds L" ``
+. ds R" ''
+'br\}
+.\"
+.\" Escape single quotes in literal strings from groff's Unicode transform.
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\"
+.\" If the F register is turned on, we'll generate index entries on stderr for
+.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
+.\" entries marked with X<> in POD. Of course, you'll have to process the
+.\" output yourself in some meaningful fashion.
+.ie \nF \{\
+. de IX
+. tm Index:\\$1\t\\n%\t"\\$2"
+..
+. nr % 0
+. rr F
+.\}
+.el \{\
+. de IX
+..
+.\}
+.\"
+.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
+.\" Fear. Run. Save yourself. No user-serviceable parts.
+. \" fudge factors for nroff and troff
+.if n \{\
+. ds #H 0
+. ds #V .8m
+. ds #F .3m
+. ds #[ \f1
+. ds #] \fP
+.\}
+.if t \{\
+. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
+. ds #V .6m
+. ds #F 0
+. ds #[ \&
+. ds #] \&
+.\}
+. \" simple accents for nroff and troff
+.if n \{\
+. ds ' \&
+. ds ` \&
+. ds ^ \&
+. ds , \&
+. ds ~ ~
+. ds /
+.\}
+.if t \{\
+. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
+. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
+. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
+. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
+. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
+. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
+.\}
+. \" troff and (daisy-wheel) nroff accents
+.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
+.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
+.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
+.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
+.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
+.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
+.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
+.ds ae a\h'-(\w'a'u*4/10)'e
+.ds Ae A\h'-(\w'A'u*4/10)'E
+. \" corrections for vroff
+.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
+.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
+. \" for low resolution devices (crt and lpr)
+.if \n(.H>23 .if \n(.V>19 \
+\{\
+. ds : e
+. ds 8 ss
+. ds o a
+. ds d- d\h'-1'\(ga
+. ds D- D\h'-1'\(hy
+. ds th \o'bp'
+. ds Th \o'LP'
+. ds ae ae
+. ds Ae AE
+.\}
+.rm #[ #] #H #V #F C
+.\" ========================================================================
+.\"
+.IX Title "Scalar::Util 3"
+.TH Scalar::Util 3 "2009-11-14" "perl v5.8.7" "User Contributed Perl Documentation"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
+.SH "NAME"
+Scalar::Util \- A selection of general\-utility scalar subroutines
+.SH "SYNOPSIS"
+.IX Header "SYNOPSIS"
+.Vb 3
+\& use Scalar::Util qw(blessed dualvar isweak readonly refaddr reftype tainted
+\& weaken isvstring looks_like_number set_prototype);
+\& # and other useful utils appearing below
+.Ve
+.SH "DESCRIPTION"
+.IX Header "DESCRIPTION"
+\&\f(CW\*(C`Scalar::Util\*(C'\fR contains a selection of subroutines that people have
+expressed would be nice to have in the perl core, but the usage would
+not really be high enough to warrant the use of a keyword, and the size
+so small such that being individual extensions would be wasteful.
+.PP
+By default \f(CW\*(C`Scalar::Util\*(C'\fR does not export any subroutines. The
+subroutines defined are
+.IP "blessed \s-1EXPR\s0" 4
+.IX Item "blessed EXPR"
+If \s-1EXPR\s0 evaluates to a blessed reference the name of the package
+that it is blessed into is returned. Otherwise \f(CW\*(C`undef\*(C'\fR is returned.
+.Sp
+.Vb 2
+\& $scalar = "foo";
+\& $class = blessed $scalar; # undef
+\&
+\& $ref = [];
+\& $class = blessed $ref; # undef
+\&
+\& $obj = bless [], "Foo";
+\& $class = blessed $obj; # "Foo"
+.Ve
+.IP "dualvar \s-1NUM\s0, \s-1STRING\s0" 4
+.IX Item "dualvar NUM, STRING"
+Returns a scalar that has the value \s-1NUM\s0 in a numeric context and the
+value \s-1STRING\s0 in a string context.
+.Sp
+.Vb 3
+\& $foo = dualvar 10, "Hello";
+\& $num = $foo + 2; # 12
+\& $str = $foo . " world"; # Hello world
+.Ve
+.IP "isvstring \s-1EXPR\s0" 4
+.IX Item "isvstring EXPR"
+If \s-1EXPR\s0 is a scalar which was coded as a vstring the result is true.
+.Sp
+.Vb 3
+\& $vs = v49.46.48;
+\& $fmt = isvstring($vs) ? "%vd" : "%s"; #true
+\& printf($fmt,$vs);
+.Ve
+.IP "isweak \s-1EXPR\s0" 4
+.IX Item "isweak EXPR"
+If \s-1EXPR\s0 is a scalar which is a weak reference the result is true.
+.Sp
+.Vb 4
+\& $ref = \e$foo;
+\& $weak = isweak($ref); # false
+\& weaken($ref);
+\& $weak = isweak($ref); # true
+.Ve
+.Sp
+\&\fB\s-1NOTE\s0\fR: Copying a weak reference creates a normal, strong, reference.
+.Sp
+.Vb 2
+\& $copy = $ref;
+\& $weak = isweak($copy); # false
+.Ve
+.IP "looks_like_number \s-1EXPR\s0" 4
+.IX Item "looks_like_number EXPR"
+Returns true if perl thinks \s-1EXPR\s0 is a number. See
+\&\*(L"looks_like_number\*(R" in perlapi.
+.IP "openhandle \s-1FH\s0" 4
+.IX Item "openhandle FH"
+Returns \s-1FH\s0 if \s-1FH\s0 may be used as a filehandle and is open, or \s-1FH\s0 is a tied
+handle. Otherwise \f(CW\*(C`undef\*(C'\fR is returned.
+.Sp
+.Vb 4
+\& $fh = openhandle(*STDIN); # \e*STDIN
+\& $fh = openhandle(\e*STDIN); # \e*STDIN
+\& $fh = openhandle(*NOTOPEN); # undef
+\& $fh = openhandle("scalar"); # undef
+.Ve
+.IP "readonly \s-1SCALAR\s0" 4
+.IX Item "readonly SCALAR"
+Returns true if \s-1SCALAR\s0 is readonly.
+.Sp
+.Vb 1
+\& sub foo { readonly($_[0]) }
+\&
+\& $readonly = foo($bar); # false
+\& $readonly = foo(0); # true
+.Ve
+.IP "refaddr \s-1EXPR\s0" 4
+.IX Item "refaddr EXPR"
+If \s-1EXPR\s0 evaluates to a reference the internal memory address of
+the referenced value is returned. Otherwise \f(CW\*(C`undef\*(C'\fR is returned.
+.Sp
+.Vb 3
+\& $addr = refaddr "string"; # undef
+\& $addr = refaddr \e$var; # eg 12345678
+\& $addr = refaddr []; # eg 23456784
+\&
+\& $obj = bless {}, "Foo";
+\& $addr = refaddr $obj; # eg 88123488
+.Ve
+.IP "reftype \s-1EXPR\s0" 4
+.IX Item "reftype EXPR"
+If \s-1EXPR\s0 evaluates to a reference the type of the variable referenced
+is returned. Otherwise \f(CW\*(C`undef\*(C'\fR is returned.
+.Sp
+.Vb 3
+\& $type = reftype "string"; # undef
+\& $type = reftype \e$var; # SCALAR
+\& $type = reftype []; # ARRAY
+\&
+\& $obj = bless {}, "Foo";
+\& $type = reftype $obj; # HASH
+.Ve
+.IP "set_prototype \s-1CODEREF\s0, \s-1PROTOTYPE\s0" 4
+.IX Item "set_prototype CODEREF, PROTOTYPE"
+Sets the prototype of the given function, or deletes it if \s-1PROTOTYPE\s0 is
+undef. Returns the \s-1CODEREF\s0.
+.Sp
+.Vb 1
+\& set_prototype \e&foo, \*(Aq$$\*(Aq;
+.Ve
+.IP "tainted \s-1EXPR\s0" 4
+.IX Item "tainted EXPR"
+Return true if the result of \s-1EXPR\s0 is tainted
+.Sp
+.Vb 2
+\& $taint = tainted("constant"); # false
+\& $taint = tainted($ENV{PWD}); # true if running under \-T
+.Ve
+.IP "weaken \s-1REF\s0" 4
+.IX Item "weaken REF"
+\&\s-1REF\s0 will be turned into a weak reference. This means that it will not
+hold a reference count on the object it references. Also when the reference
+count on that object reaches zero, \s-1REF\s0 will be set to undef.
+.Sp
+This is useful for keeping copies of references , but you don't want to
+prevent the object being DESTROY-ed at its usual time.
+.Sp
+.Vb 6
+\& {
+\& my $var;
+\& $ref = \e$var;
+\& weaken($ref); # Make $ref a weak reference
+\& }
+\& # $ref is now undef
+.Ve
+.Sp
+Note that if you take a copy of a scalar with a weakened reference,
+the copy will be a strong reference.
+.Sp
+.Vb 4
+\& my $var;
+\& my $foo = \e$var;
+\& weaken($foo); # Make $foo a weak reference
+\& my $bar = $foo; # $bar is now a strong reference
+.Ve
+.Sp
+This may be less obvious in other situations, such as \f(CW\*(C`grep()\*(C'\fR, for instance
+when grepping through a list of weakened references to objects that may have
+been destroyed already:
+.Sp
+.Vb 1
+\& @object = grep { defined } @object;
+.Ve
+.Sp
+This will indeed remove all references to destroyed objects, but the remaining
+references to objects will be strong, causing the remaining objects to never
+be destroyed because there is now always a strong reference to them in the
+\&\f(CW@object\fR array.
+.SH "DIAGNOSTICS"
+.IX Header "DIAGNOSTICS"
+Module use may give one of the following errors during import.
+.IP "Weak references are not implemented in the version of perl" 4
+.IX Item "Weak references are not implemented in the version of perl"
+The version of perl that you are using does not implement weak references, to use
+\&\f(CW\*(C`isweak\*(C'\fR or \f(CW\*(C`weaken\*(C'\fR you will need to use a newer release of perl.
+.IP "Vstrings are not implemented in the version of perl" 4
+.IX Item "Vstrings are not implemented in the version of perl"
+The version of perl that you are using does not implement Vstrings, to use
+\&\f(CW\*(C`isvstring\*(C'\fR you will need to use a newer release of perl.
+.ie n .IP """NAME"" is only available with the \s-1XS\s0 version of Scalar::Util" 4
+.el .IP "\f(CWNAME\fR is only available with the \s-1XS\s0 version of Scalar::Util" 4
+.IX Item "NAME is only available with the XS version of Scalar::Util"
+\&\f(CW\*(C`Scalar::Util\*(C'\fR contains both perl and C implementations of many of its functions
+so that those without access to a C compiler may still use it. However some of the functions
+are only available when a C compiler was available to compile the \s-1XS\s0 version of the extension.
+.Sp
+At present that list is: weaken, isweak, dualvar, isvstring, set_prototype
+.SH "KNOWN BUGS"
+.IX Header "KNOWN BUGS"
+There is a bug in perl5.6.0 with \s-1UV\s0's that are >= 1<<31. This will
+show up as tests 8 and 9 of dualvar.t failing
+.SH "SEE ALSO"
+.IX Header "SEE ALSO"
+List::Util
+.SH "COPYRIGHT"
+.IX Header "COPYRIGHT"
+Copyright (c) 1997\-2007 Graham Barr <gbarr@pobox.com>. All rights reserved.
+This program is free software; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+.PP
+Except weaken and isweak which are
+.PP
+Copyright (c) 1999 Tuomas J. Lukka <lukka@iki.fi>. All rights reserved.
+This program is free software; you can redistribute it and/or modify it
+under the same terms as perl itself.
projects / catagits/Gitalist.git / blobdiff