// should NOT alter refcount
Node* set_parent(Node* self, Node* parent) {
    self->parent = parent;
    return self;
}
[download]

void set_parent(Node* self, Node* parent) {
    self->parent = parent;
}
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#!perl -l
use warnings;
no warnings 'once';

use Inline C  => Config =>
 BUILD_NOISY => 1;

use Inline C => <<'EOC';

SV * foo(SV * in) {
 return in;
}

SV * get_ref(SV * in) {
 return newSVuv(SvREFCNT(in));
}

EOC

$x = 42;       # $x refcnt == 1
%h = (fu => \$x); # $x refcnt == 2
print "x refcnt: ", get_ref($x);

foo($x); # decrement $x refcnt
print "x refcnt: ", get_ref($x);

$y = foo($x); # decrement $x refcnt
print "x refcnt: ", get_ref($x);
print "y refcnt: ", get_ref($y);

print "x: $x";
print "y: $y";
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x refcnt: 2
x refcnt: 1
x refcnt: 0
y refcnt: 1
Use of uninitialized value $x in concatenation (.) or string at try.pl
+ line 31.
x:
y: 42
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Node* get_parent(Node* self) {
   SvREFCNT_inc(self->parent);
   return self->parent;
}
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NODE: SV = IV(0x2c22740) at 0x2c22744
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  RV = 0x45812c
  SV = PVMG(0x2a15cac) at 0x45812c
    REFCNT = 1
    FLAGS = (OBJECT,IOK,READONLY,pIOK)
    IV = 40118476
    NV = 0
    PV = 0
    STASH = 0x1d0edb4   "Node"
---
PARENT: SV = IV(0x2c227f0) at 0x2c227f4
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  RV = 0x45807c
  SV = PVMG(0x2a155ac) at 0x45807c
    REFCNT = 1
    FLAGS = (OBJECT,IOK,READONLY,pIOK)
    IV = 40119340
    NV = 0
    PV = 0
    STASH = 0x1d0edb4   "Node"
---
FROM FIELD: SV = NULL(0x1d0e7) at 0x45817d
  REFCNT = -16777216
  FLAGS = (TEMP,BREAK,OVERLOAD,EVALED,IsUV)
---
destroying Node=SCALAR(0x45807c) at rut.pl line 58.
destroying Node=SCALAR(0x45812c) at rut.pl line 58.
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void destroy_node(Node* self) {
     Safefree(self->parent);
     Safefree(self);
}
[download]