Manpages - B_Op_private.3perl
Table of Contents
NAME
B::Op_private - OP op_private flag definitions
SYNOPSIS
use B::Op_private; # flag details for bit 7 of OP_AELEMs op_private: my $name = $B::Op_private::bits{aelem}{7}; # OPpLVAL_INTRO my $value = $B::Op_private::defines{$name}; # 128 my $label = $B::Op_private::labels{$name}; # LVINTRO # the bit field at bits 5..6 of OP_AELEMs op_private: my $bf = $B::Op_private::bits{aelem}{6}; my $mask = $bf->{bitmask}; # etc
DESCRIPTION
This module provides four global hashes:
%B::Op_private::bits %B::Op_private::defines %B::Op_private::labels %B::Op_private::ops_using
which contain information about the per-op meanings of the bits in the op_private field.
%bits
This is indexed by op name and then bit number (0..7). For single bit flags, it returns the name of the define (if any) for that bit:
$B::Op_private::bits{aelem}{7} eq OPpLVAL_INTRO;
For bit fields, it returns a hash ref containing details about the field. The same reference will be returned for all bit positions that make up the bit field; so for example these both return the same hash ref:
$bitfield = $B::Op_private::bits{aelem}{5}; $bitfield = $B::Op_private::bits{aelem}{6};
The general format of this hash ref is
{ # The bit range and mask; these are always present. bitmin > 5,
bitmax => 6, bitmask => 0x60, # (The remaining keys are optional) # The
names of any defines that were requested: mask_def => OPpFOO_MASK,
baseshift_def => OPpFOO_SHIFT, bitcount_def => OPpFOO_BITS, # If
present, Concise etc will display the value with a FOO # prefix. If it
equals -, then Concise will treat the bit # field as raw bits and not
try to interpret it. label => FOO, # If present, specifies the names of
some defines and the # display labels that are used to assign meaning to
particu- # lar integer values within the bit field; e.g. 3 is dis- #
played as C. enum => [ qw( 1 OPpFOO_A A 2 OPpFOO_B B 3 OPpFOO_C C )], };
%defines
This gives the value of every OPp define, e.g.
$B::Op_private::defines{OPpLVAL_INTRO} == 128;
%labels
This gives the short display label for each define, as used by
B::Concise and perl -Dx, e.g.
$B::Op_private::labels{OPpLVAL_INTRO} eq LVINTRO;
If the label equals ’-’, then Concise will treat the bit as a raw bit and not try to display it symbolically.
%ops_using
For each define, this gives a reference to an array of op names that use the flag.
@ops_using_lvintro = @{ $B::Op_private::ops_using{OPp_LVAL_INTRO} };