B::Op_private(3pm) Perl Programmers Reference Guide B::Op_private(3pm)
NAME
B::Op_private - OP op_private flag definitions
SYNOPSIS
use B::Op_private;
# flag details for bit 7 of OP_AELEM's 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_AELEM's 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} };
perl v5.24.0 2016-05-08 B::Op_private(3pm)
perl 5.24 - Generated Thu Nov 3 16:04:28 CDT 2016