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Revision 1.3 by root, Wed Feb 7 21:34:02 2007 UTC vs.
Revision 1.6 by root, Sat Apr 26 03:15:28 2008 UTC

… …
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(0x7bd2d0) is
36 in the global $Test::var.
36 referenced by REF(0x676fb0), which is 37 referenced by REF(0x7bd240), which is
38 in the member 'ukukey2' of HASH(0x7bd228), which is
39 referenced by REF(0x81dae8), which is
40 in the lexical '$local' in CODE(0x81da88), which is
41 in the global &Test::testsub.
42 referenced by REF(0x81da40), which is
43 in the global $Test::hash2.
44 referenced by REF(0x79f3f8), which is
37 in the lexical '$x' in CODE(0x676370), which is 45 in the lexical '$x' in CODE(0x79f518), which is
46 the containing scope for CODE(0x81da88), which is
47 in the global &Test::testsub.
48 referenced by REF(0x79f2f0), which is
38 not found anywhere I looked :( 49 not found anywhere I looked :(
39 referenced by REF(0x676360), which is 50 referenced by REF(0x79f140), which is
40 in the member 'ukukey' of HASH(0x756660), which is 51 in the member 'ukukey' of HASH(0x81d698), which is
41 in the global %Test::hash. 52 in the global %Test::hash.
42 in the global $Test::var.
43 referenced by REF(0x6760e0), which is
44 in the member 'ukukey2' of HASH(0x676f30), which is
45 referenced by REF(0x77bcf0), which is
46 in the lexical '$local' in CODE(0x77bcb0), which is
47 in the global &Test::testsub.
48 referenced by REF(0x77bc80), which is
49 in the global $Test::hash2.
50 53
51 It is a bit convoluted to read, but basically it says that the value 54 It is a bit convoluted to read, but basically it says that the value
52 stored in $var can be found: 55 stored in $var can be found:
53 56
54 - in some variable $x whose origin is not known (I frankly have no idea 57 - in some variable $x whose origin is not known (I frankly have no idea
… …
59 - in the hash element "ukukey2", in the hash in the my variable $local 62 - in the hash element "ukukey2", in the hash in the my variable $local
60 in the sub "Test::testsub" and also in the hash referenced by 63 in the sub "Test::testsub" and also in the hash referenced by
61 $Test::hash2. 64 $Test::hash2.
62 65
63EXPORTS 66EXPORTS
64 None. 67 None.
65 68
66FUNCTIONS 69FUNCTIONS
67 $string = Devel::FindRef::track $ref[, $depth] 70 $string = Devel::FindRef::track $ref[, $depth]
68 Track the perl value pointed to by $ref up to a depth of $depth 71 Track the perl value pointed to by $ref up to a depth of $depth and
69 and return a descriptive string. $ref can point at any perl 72 return a descriptive string. $ref can point at any perl value, be it
70 value, be it anonymous sub, hash, array, scalar etc. 73 anonymous sub, hash, array, scalar etc.
71 74
72 This is the function you most often use. 75 This is the function you most often use.
73 76
74 @references = Devel::FindRef::find $ref 77 @references = Devel::FindRef::find $ref
75 Return arrayrefs that contain [$message, $ref] pairs. The 78 Return arrayrefs that contain [$message, $ref] pairs. The message
76 message describes what kind of reference was found and the $ref 79 describes what kind of reference was found and the $ref is the
77 is the reference itself, which cna be omitted if "find" decided 80 reference itself, which can be omitted if "find" decided to end the
78 to end the search. 81 search. The returned references are all weak references.
79 82
80 The "track" function uses this to find references to the value 83 The "track" function uses this to find references to the value you
81 you are interested in and recurses on the returned references. 84 are interested in and recurses on the returned references.
82 85
83 $ref = Devel::FindRef::ref2ptr $ptr 86 $ref = Devel::FindRef::ptr2ref $integer
84 Sometimes you know (from debugging output) the address of a perl 87 Sometimes you know (from debugging output) the address of a perl
85 scalar you are interested in. This function can be used to turn 88 scalar you are interested in (e.g. "HASH(0x176ff70)"). This function
86 the address into a reference to that scalar. It is quite safe to 89 can be used to turn the address into a reference to that scalar. It
87 call on valid addresses, but extremely dangerous to call on 90 is quite safe to call on valid addresses, but extremely dangerous to
88 invalid ones. 91 call on invalid ones.
92
93 # we know that HASH(0x176ff70) exists, so turn it into a hashref:
94 my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70;
89 95
90AUTHOR 96AUTHOR
91 Marc Lehmann <pcg@goof.com>. 97 Marc Lehmann <pcg@goof.com>.
92 98
93BUGS 99BUGS
94 Only code values, arrays, hashes, scalars and magic are being looked 100 Only code values, arrays, hashes, scalars and magic are being looked at.
95 at.
96 101
97 This is a quick hack only. 102 This is a quick hack only.
98 103
99COPYRIGHT AND LICENSE 104COPYRIGHT AND LICENSE
100 Copyright (C) 2007 by Marc Lehmann. 105 Copyright (C) 2007 by Marc Lehmann.
101 106
102 This library is free software; you can redistribute it and/or modify 107 This library is free software; you can redistribute it and/or modify it
103 it under the same terms as Perl itself, either Perl version 5.8.8 108 under the same terms as Perl itself, either Perl version 5.8.8 or, at
104 or, at your option, any later version of Perl 5 you may have 109 your option, any later version of Perl 5 you may have available.
105 available.
106 110

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