1MCE::Shared::Scalar(3)User Contributed Perl DocumentationMCE::Shared::Scalar(3)
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NAME

6       MCE::Shared::Scalar - Scalar helper class
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VERSION

9       This document describes MCE::Shared::Scalar version 1.877
10

DESCRIPTION

12       A scalar helper class for use as a standalone or managed by
13       MCE::Shared.
14

SYNOPSIS

16        # non-shared or local construction for use by a single process
17
18        use MCE::Shared::Scalar;
19
20        my $var = MCE::Shared::Scalar->new( $val );
21
22        # construction for sharing with other threads and processes
23
24        use MCE::Shared;
25
26        my $var = MCE::Shared->scalar( $val );
27
28        # scalar-like dereferencing
29
30        my $val = ${ $var };
31        ${ $var } = $val;
32
33        # OO interface
34
35        $val = $var->set( $val );
36        $val = $var->get();
37        $len = $var->len();
38
39        # included, sugar methods without having to call set/get explicitly
40
41        $val = $var->append( $string );     #   $val .= $string
42        $val = $var->decr();                # --$val
43        $val = $var->decrby( $number );     #   $val -= $number
44        $val = $var->getdecr();             #   $val--
45        $val = $var->getincr();             #   $val++
46        $val = $var->incr();                # ++$val
47        $val = $var->incrby( $number );     #   $val += $number
48        $old = $var->getset( $new );        #   $o = $v, $v = $n, $o
49
50       For normal scalar behavior, the TIE interface is supported.
51
52        # non-shared or local construction for use by a single process
53
54        use MCE::Shared::Scalar;
55
56        tie my $var, "MCE::Shared::Scalar";
57
58        # construction for sharing with other threads and processes
59
60        use MCE::Shared;
61
62        tie my $var, "MCE::Shared";
63
64        # usage
65
66        $var = 0;
67
68        tied($var)->incrby(20);
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API DOCUMENTATION

71       This module may involve TIE when accessing the object via scalar
72       dereferencing.  Only shared instances are impacted if doing so.
73       Although likely fast enough for many use cases, the OO interface is
74       recommended for best performance.
75
76   MCE::Shared::Scalar->new ( [ value ] )
77   MCE::Shared->scalar ( [ value ] )
78       Constructs a new object. Its value is undefined when "value" is not
79       specified.
80
81        # non-shared or local construction for use by a single process
82
83        use MCE::Shared::Scalar;
84
85        $var = MCE::Shared::Scalar->new( "foo" );
86        $var = MCE::Shared::Scalar->new;
87
88        # construction for sharing with other threads and processes
89
90        use MCE::Shared;
91
92        $var = MCE::Shared->scalar( "bar" );
93        $var = MCE::Shared->scalar;
94
95   set ( value )
96       Preferably, set the value via the OO interface. Otherwise, "TIE" is
97       activated on-demand for setting the value. The new value is returned in
98       scalar context.
99
100        $val = $var->set( "baz" );
101        $var->set( "baz" );
102        ${$var} = "baz";
103
104   get
105       Likewise, obtain the value via the OO interface. "TIE" is utilized for
106       retrieving the value otherwise.
107
108        $val = $var->get;
109        $val = ${$var};
110
111   len
112       Returns the length of the value. It returns the "undef" value if the
113       value is not defined.
114
115        $len = $var->len;
116        length ${$var};
117

SUGAR METHODS

119       This module is equipped with sugar methods to not have to call "set"
120       and "get" explicitly. In shared context, the benefit is atomicity and
121       reduction in inter-process communication.
122
123       The API resembles a subset of the Redis primitives
124       <https://redis.io/commands#strings> without the key argument.
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126   append ( value )
127       Appends a value at the end of the current value and returns its new
128       length.
129
130        $len = $var->append( "foo" );
131
132   decr
133       Decrements the value by one and returns its new value.
134
135        $num = $var->decr;
136
137   decrby ( number )
138       Decrements the value by the given number and returns its new value.
139
140        $num = $var->decrby( 2 );
141
142   getdecr
143       Decrements the value by one and returns its old value.
144
145        $old = $var->getdecr;
146
147   getincr
148       Increments the value by one and returns its old value.
149
150        $old = $var->getincr;
151
152   getset ( value )
153       Sets the value and returns its old value.
154
155        $old = $var->getset( "baz" );
156
157   incr
158       Increments the value by one and returns its new value.
159
160        $num = $var->incr;
161
162   incrby ( number )
163       Increments the value by the given number and returns its new value.
164
165        $num = $var->incrby( 2 );
166

CREDITS

168       The implementation is inspired by Tie::StdScalar.
169

INDEX

171       MCE, MCE::Hobo, MCE::Shared
172

AUTHOR

174       Mario E. Roy, <marioeroy AT gmail DOT com>
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178perl v5.36.0                      2022-07-22            MCE::Shared::Scalar(3)