In both case, we have scalars of the same type (PVIO). But just like an IV can hold more than one kind of data, PVIO can contain one of two types of handles. I'll clarify that in my table.

By the way, you didn't show the difference, so here goes: 

$ perl -MDevel::Peek -we'open FH,$^X; Dump *FH{IO}'
SV = IV(0x7564a8) at 0x7564b0
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x7693f0
  SV = PVIO(0x76ccb8) at 0x7693f0
    REFCNT = 2
    FLAGS = (OBJECT)
    STASH = 0x768b68    "IO::File"
    IFP = 0x763b30
    OFP = 0x0
    DIRP = 0x0
    LINES = 0
    PAGE = 0
    PAGE_LEN = 60
    LINES_LEFT = 0
    TOP_GV = 0x0
    FMT_GV = 0x0
    BOTTOM_GV = 0x0
    TYPE = '<'
    FLAGS = 0x0

$ perl -MDevel::Peek -we'opendir DH,"."; Dump *DH{IO}'
SV = IV(0x759d18) at 0x759d20
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x76cc78
  SV = PVIO(0x770528) at 0x76cc78
    REFCNT = 2
    FLAGS = (OBJECT)
    STASH = 0x76c3d8    "IO::File"
    IFP = 0x0
    OFP = 0x0
    DIRP = 0x7a7330
    LINES = 0
    PAGE = 0
    PAGE_LEN = 60
    LINES_LEFT = 0
    TOP_GV = 0x0
    FMT_GV = 0x0
    BOTTOM_GV = 0x0
    TYPE = '\0'
    FLAGS = 0x0

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In reply to Re^3: Where to find info on low level perl internals names? by ikegami
in thread Where to find info on low level perl internals names? by Anonymous Monk

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