Re^2: how internally $#array is working in Perl

Actually, because $#array can be used as an lvalue, a fair bit of magic is going on (including adding "magic" to both the returned scalar and the array in some circumstances). Fortunately, it is invisible to the user.

$ perl -MDevel::Peek -e'my @a; Dump(\@a,1); Dump($#a); Dump(\@a,1);'
SV = IV(0x816c154) at 0x816c158
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x817bc30
  SV = PVAV(0x816d038) at 0x817bc30
    REFCNT = 2
    FLAGS = (PADMY)
    ARRAY = 0x0
    FILL = -1
    MAX = -1
    ARYLEN = 0x0
    FLAGS = (REAL)
SV = PVMG(0x817718c) at 0x816c158
  REFCNT = 1
  FLAGS = (GMG,SMG)
  IV = 0
  NV = 0
  PV = 0
  MAGIC = 0x8194008
    MG_VIRTUAL = &PL_vtbl_arylen
    MG_TYPE = PERL_MAGIC_arylen(#)
    MG_OBJ = 0x817bc30
SV = IV(0x816c2b4) at 0x816c2b8
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x817bc30
  SV = PVAV(0x816d038) at 0x817bc30
    REFCNT = 2
    FLAGS = (PADMY,RMG)
    MAGIC = 0x8193420
      MG_VIRTUAL = &PL_vtbl_arylen_p
      MG_TYPE = PERL_MAGIC_arylen_p(@)
      MG_FLAGS = 0x02
        REFCOUNTED
      MG_OBJ = 0x816c158
      SV = PVMG(0x817718c) at 0x816c158
        REFCNT = 1
        FLAGS = (GMG,SMG)
        IV = 0
        NV = 0
        PV = 0
        MAGIC = 0x8194008
          MG_VIRTUAL = &PL_vtbl_arylen
          MG_TYPE = PERL_MAGIC_arylen(#)
          MG_OBJ = 0x817bc30
    ARRAY = 0x0
    FILL = -1
    MAX = -1
    ARYLEN = 0x816c158
    FLAGS = (REAL)
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