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diff --git a/upstream/debian-unstable/man3/Scalar::Util.3perl b/upstream/debian-unstable/man3/Scalar::Util.3perl new file mode 100644 index 00000000..7253d88d --- /dev/null +++ b/upstream/debian-unstable/man3/Scalar::Util.3perl @@ -0,0 +1,430 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) +.\" +.\" 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 +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'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 >0, 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. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" ======================================================================== +.\" +.IX Title "Scalar::Util 3perl" +.TH Scalar::Util 3perl 2024-01-12 "perl v5.38.2" "Perl Programmers Reference Guide" +.\" 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 4 +\& use Scalar::Util qw(blessed dualvar isdual readonly refaddr reftype +\& tainted weaken isweak 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 would be so small that +being individual extensions would be wasteful. +.PP +By default \f(CW\*(C`Scalar::Util\*(C'\fR does not export any subroutines. +.ie n .SS "Core Perl ""builtin"" Functions" +.el .SS "Core Perl \f(CWbuiltin\fP Functions" +.IX Subsection "Core Perl builtin Functions" +Many functions in this module have served as the inspiration for a new +experimental facility in recent versions of Perl. From various development +versions, starting at 5.35.7, equivalent functions to many of these utilities +are available in the \f(CW\*(C`builtin::\*(C'\fR package. +.PP +.Vb 1 +\& use Scalar::Util qw(blessed); +\& +\& $class = blessed $obj; +\& +\& $class = builtin::blessed $obj; # equivalent +.Ve +.PP +For more information, see the documentation on builtin. +.SH "FUNCTIONS FOR REFERENCES" +.IX Header "FUNCTIONS FOR REFERENCES" +The following functions all perform some useful activity on reference values. +.SS blessed +.IX Subsection "blessed" +.Vb 1 +\& my $pkg = blessed( $ref ); +.Ve +.PP +If \f(CW$ref\fR is a blessed reference, the name of the package that it is blessed +into is returned. Otherwise \f(CW\*(C`undef\*(C'\fR is returned. +.PP +.Vb 2 +\& $scalar = "foo"; +\& $class = blessed $scalar; # undef +\& +\& $ref = []; +\& $class = blessed $ref; # undef +\& +\& $obj = bless [], "Foo"; +\& $class = blessed $obj; # "Foo" +.Ve +.PP +Take care when using this function simply as a truth test (such as in +\&\f(CW\*(C`if(blessed $ref)...\*(C'\fR) because the package name \f(CW"0"\fR is defined yet false. +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::blessed\*(C'\fR. +.SS refaddr +.IX Subsection "refaddr" +.Vb 1 +\& my $addr = refaddr( $ref ); +.Ve +.PP +If \f(CW$ref\fR is reference, the internal memory address of the referenced value is +returned as a plain integer. Otherwise \f(CW\*(C`undef\*(C'\fR is returned. +.PP +.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 +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::refaddr\*(C'\fR. +.SS reftype +.IX Subsection "reftype" +.Vb 1 +\& my $type = reftype( $ref ); +.Ve +.PP +If \f(CW$ref\fR is a reference, the basic Perl type of the variable referenced is +returned as a plain string (such as \f(CW\*(C`ARRAY\*(C'\fR or \f(CW\*(C`HASH\*(C'\fR). Otherwise \f(CW\*(C`undef\*(C'\fR +is returned. +.PP +.Vb 3 +\& $type = reftype "string"; # undef +\& $type = reftype \e$var; # SCALAR +\& $type = reftype []; # ARRAY +\& +\& $obj = bless {}, "Foo"; +\& $type = reftype $obj; # HASH +.Ve +.PP +Note that for internal reasons, all precompiled regexps (\f(CW\*(C`qr/.../\*(C'\fR) are +blessed references; thus \f(CWref()\fR returns the package name string \f(CW"Regexp"\fR +on these but \f(CWreftype()\fR will return the underlying C structure type of +\&\f(CW"REGEXP"\fR in all capitals. +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::reftype\*(C'\fR. +.SS weaken +.IX Subsection "weaken" +.Vb 1 +\& weaken( $ref ); +.Ve +.PP +The lvalue \f(CW$ref\fR 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, the reference will be set to +undef. This function mutates the lvalue passed as its argument and returns no +value. +.PP +This is useful for keeping copies of references, but you don't want to prevent +the object being DESTROY-ed at its usual time. +.PP +.Vb 6 +\& { +\& my $var; +\& $ref = \e$var; +\& weaken($ref); # Make $ref a weak reference +\& } +\& # $ref is now undef +.Ve +.PP +Note that if you take a copy of a scalar with a weakened reference, the copy +will be a strong reference. +.PP +.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 +.PP +This may be less obvious in other situations, such as \f(CWgrep()\fR, for instance +when grepping through a list of weakened references to objects that may have +been destroyed already: +.PP +.Vb 1 +\& @object = grep { defined } @object; +.Ve +.PP +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. +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::weaken\*(C'\fR. +.SS unweaken +.IX Subsection "unweaken" +.Vb 1 +\& unweaken( $ref ); +.Ve +.PP +\&\fISince version 1.36.\fR +.PP +The lvalue \f(CW\*(C`REF\*(C'\fR will be turned from a weak reference back into a normal +(strong) reference again. This function mutates the lvalue passed as its +argument and returns no value. This undoes the action performed by +"weaken". +.PP +This function is slightly neater and more convenient than the +otherwise-equivalent code +.PP +.Vb 3 +\& my $tmp = $REF; +\& undef $REF; +\& $REF = $tmp; +.Ve +.PP +(because in particular, simply assigning a weak reference back to itself does +not work to unweaken it; \f(CW\*(C`$REF = $REF\*(C'\fR does not work). +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::unweaken\*(C'\fR. +.SS isweak +.IX Subsection "isweak" +.Vb 1 +\& my $weak = isweak( $ref ); +.Ve +.PP +Returns true if \f(CW$ref\fR is a weak reference. +.PP +.Vb 4 +\& $ref = \e$foo; +\& $weak = isweak($ref); # false +\& weaken($ref); +\& $weak = isweak($ref); # true +.Ve +.PP +\&\fBNOTE\fR: Copying a weak reference creates a normal, strong, reference. +.PP +.Vb 2 +\& $copy = $ref; +\& $weak = isweak($copy); # false +.Ve +.PP +\&\fISince Perl version 5.35.7\fR an equivalent function is available as +\&\f(CW\*(C`builtin::is_weak\*(C'\fR. +.SH "OTHER FUNCTIONS" +.IX Header "OTHER FUNCTIONS" +.SS dualvar +.IX Subsection "dualvar" +.Vb 1 +\& my $var = dualvar( $num, $string ); +.Ve +.PP +Returns a scalar that has the value \f(CW$num\fR in a numeric context and the value +\&\f(CW$string\fR in a string context. +.PP +.Vb 3 +\& $foo = dualvar 10, "Hello"; +\& $num = $foo + 2; # 12 +\& $str = $foo . " world"; # Hello world +.Ve +.SS isdual +.IX Subsection "isdual" +.Vb 1 +\& my $dual = isdual( $var ); +.Ve +.PP +\&\fISince version 1.26.\fR +.PP +If \f(CW$var\fR is a scalar that has both numeric and string values, the result is +true. +.PP +.Vb 2 +\& $foo = dualvar 86, "Nix"; +\& $dual = isdual($foo); # true +.Ve +.PP +Note that a scalar can be made to have both string and numeric content through +standard operations: +.PP +.Vb 4 +\& $foo = "10"; +\& $dual = isdual($foo); # false +\& $bar = $foo + 0; +\& $dual = isdual($foo); # true +.Ve +.PP +The \f(CW$!\fR variable is commonly dual-valued, though it is also magical in other +ways: +.PP +.Vb 3 +\& $! = 1; +\& $dual = isdual($!); # true +\& print("$!\en"); # "Operation not permitted" +.Ve +.PP +\&\fBCAUTION\fR: This function is not as useful as it may seem. Dualvars are not a +distinct concept in Perl, but a standard internal construct of all scalar +values. Almost any value could be considered as a dualvar by this function +through the course of normal operations. +.SS isvstring +.IX Subsection "isvstring" +.Vb 1 +\& my $vstring = isvstring( $var ); +.Ve +.PP +If \f(CW$var\fR is a scalar which was coded as a vstring, the result is true. +.PP +.Vb 3 +\& $vs = v49.46.48; +\& $fmt = isvstring($vs) ? "%vd" : "%s"; #true +\& printf($fmt,$vs); +.Ve +.SS looks_like_number +.IX Subsection "looks_like_number" +.Vb 1 +\& my $isnum = looks_like_number( $var ); +.Ve +.PP +Returns true if perl thinks \f(CW$var\fR is a number. See +"looks_like_number" in perlapi. +.SS openhandle +.IX Subsection "openhandle" +.Vb 1 +\& my $fh = openhandle( $fh ); +.Ve +.PP +Returns \f(CW$fh\fR itself, if \f(CW$fh\fR may be used as a filehandle and is open, or if +it is a tied handle. Otherwise \f(CW\*(C`undef\*(C'\fR is returned. +.PP +.Vb 4 +\& $fh = openhandle(*STDIN); # \e*STDIN +\& $fh = openhandle(\e*STDIN); # \e*STDIN +\& $fh = openhandle(*NOTOPEN); # undef +\& $fh = openhandle("scalar"); # undef +.Ve +.SS readonly +.IX Subsection "readonly" +.Vb 1 +\& my $ro = readonly( $var ); +.Ve +.PP +Returns true if \f(CW$var\fR is readonly. +.PP +.Vb 1 +\& sub foo { readonly($_[0]) } +\& +\& $readonly = foo($bar); # false +\& $readonly = foo(0); # true +.Ve +.SS set_prototype +.IX Subsection "set_prototype" +.Vb 1 +\& my $code = set_prototype( $code, $prototype ); +.Ve +.PP +Sets the prototype of the function given by the \f(CW$code\fR reference, or deletes +it if \f(CW$prototype\fR is \f(CW\*(C`undef\*(C'\fR. Returns the \f(CW$code\fR reference itself. +.PP +.Vb 1 +\& set_prototype \e&foo, \*(Aq$$\*(Aq; +.Ve +.SS tainted +.IX Subsection "tainted" +.Vb 1 +\& my $t = tainted( $var ); +.Ve +.PP +Return true if \f(CW$var\fR is tainted. +.PP +.Vb 2 +\& $taint = tainted("constant"); # false +\& $taint = tainted($ENV{PWD}); # true if running under \-T +.Ve +.SH DIAGNOSTICS +.IX Header "DIAGNOSTICS" +Module use may give one of the following errors during import. +.IP "Vstrings are not implemented in this version of perl" 4 +.IX Item "Vstrings are not implemented in this version of perl" +The version of perl that you are using does not implement Vstrings, to use +"isvstring" you will need to use a newer release of perl. +.SH "KNOWN BUGS" +.IX Header "KNOWN BUGS" +There is a bug in perl5.6.0 with UV'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 +Additionally "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. +.PP +Copyright (C) 2004, 2008 Matthijs van Duin. All rights reserved. +Copyright (C) 2014 cPanel Inc. All rights reserved. +This program is free software; you can redistribute it and/or modify +it under the same terms as Perl itself. |