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Revision 1.4 by root, Wed Nov 28 12:20:33 2007 UTC vs.
Revision 1.8 by root, Sat Jul 19 01:38:57 2008 UTC

1NAME 1NAME
2 Devel::FindRef - where is that reference to my scalar hiding? 2 Devel::FindRef - where is that reference to my variable hiding?
3 3
4SYNOPSIS 4SYNOPSIS
5 use Devel::FindRef; 5 use Devel::FindRef;
6 6
7DESCRIPTION 7DESCRIPTION
… …
14 to the variables containing them. 14 to the variables containing them.
15 15
16 For example, for this fragment: 16 For example, for this fragment:
17 17
18 package Test; 18 package Test;
19 19
20 our $var = "hi\n"; 20 our $var = "hi\n";
21 my $x = \$var; 21 my $x = \$var;
22 our %hash = (ukukey => \$var); 22 our %hash = (ukukey => \$var);
23 our $hash2 = {ukukey2 => \$var}; 23 our $hash2 = {ukukey2 => \$var};
24 24
25 sub testsub { 25 sub testsub {
26 my $local = $hash2; 26 my $local = $hash2;
27 print Devel::FindRef::track \$var; 27 print Devel::FindRef::track \$var;
28 } 28 }
29 29
30 testsub; 30 testsub;
31 31
32 The output is as follows (or similar to this, in case I forget to update 32 The output is as follows (or similar to this, in case I forget to update
33 the manpage after some changes): 33 the manpage after some changes):
34 34
35 SCALAR(0x676fa0) is 35 SCALAR(0x814ece8) is
36 +- in the global $Test::var.
36 referenced by REF(0x676fb0), which is 37 +- referenced by REF(0x814f9e4), which is
37 in the lexical '$x' in CODE(0x676370), which is 38 | in the lexical '$x' in CODE(0x814ed78), which is
38 not found anywhere I looked :( 39 | the containing scope for CODE(0x820c4b0), which is
40 | in the global &Test::testsub.
39 referenced by REF(0x676360), which is 41 +- referenced by REF(0x814ed6c), which is
40 in the member 'ukukey' of HASH(0x756660), which is 42 | in the member 'ukukey' of HASH(0x81da20c), which is
41 in the global %Test::hash. 43 | in the global %Test::hash.
42 in the global $Test::var.
43 referenced by REF(0x6760e0), which is 44 +- referenced by REF(0x814ec28), which is
45 | not found anywhere I looked :(
46 +- referenced by REF(0x814eb44), which is
44 in the member 'ukukey2' of HASH(0x676f30), which is 47 in the member 'ukukey2' of HASH(0x814f99c), which is
45 referenced by REF(0x77bcf0), which is 48 +- referenced by REF(0x820c450), which is
46 in the lexical '$local' in CODE(0x77bcb0), which is 49 | in the lexical '$local' in CODE(0x820c4b0), which was seen before.
47 in the global &Test::testsub.
48 referenced by REF(0x77bc80), which is 50 +- referenced by REF(0x820c204), which is
49 in the global $Test::hash2. 51 in the global $Test::hash2.
50 52
51 It is a bit convoluted to read, but basically it says that the value 53 It is a bit convoluted to read, but basically it says that the value
52 stored in $var can be found: 54 stored in $var can be found:
53 55
… …
72 This is the function you most often use. 74 This is the function you most often use.
73 75
74 @references = Devel::FindRef::find $ref 76 @references = Devel::FindRef::find $ref
75 Return arrayrefs that contain [$message, $ref] pairs. The message 77 Return arrayrefs that contain [$message, $ref] pairs. The message
76 describes what kind of reference was found and the $ref is the 78 describes what kind of reference was found and the $ref is the
77 reference itself, which cna be omitted if "find" decided to end the 79 reference itself, which can be omitted if "find" decided to end the
78 search. 80 search. The returned references are all weak references.
79 81
80 The "track" function uses this to find references to the value you 82 The "track" function uses this to find references to the value you
81 are interested in and recurses on the returned references. 83 are interested in and recurses on the returned references.
82 84
83 $ref = Devel::FindRef::ptr2ref $integer 85 $ref = Devel::FindRef::ptr2ref $integer
… …
87 is quite safe to call on valid addresses, but extremely dangerous to 89 is quite safe to call on valid addresses, but extremely dangerous to
88 call on invalid ones. 90 call on invalid ones.
89 91
90 # we know that HASH(0x176ff70) exists, so turn it into a hashref: 92 # we know that HASH(0x176ff70) exists, so turn it into a hashref:
91 my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; 93 my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70;
94
95 $ref = Devel::FindRef::ref2ptr $reference
96 The opposite of "ptr2ref", above: returns the internal address of
97 the value pointed to by the passed reference. *No checks whatsoever
98 will be done*, so don't use this.
99
100ENVIRONMENT VARIABLES
101 You can set the environment variable "PERL_DEVEL_FINDREF_DEPTH" to an
102 integer to override the default depth in "track". If a call explicitly
103 specified a depth it is not overridden.
92 104
93AUTHOR 105AUTHOR
94 Marc Lehmann <pcg@goof.com>. 106 Marc Lehmann <pcg@goof.com>.
95 107
96BUGS 108BUGS

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