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in reply to how to set a breakpoint by a code reference

I'm not sure where you are getting 
b $mysubref

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from. The doc I see says this, which seems to be the behaviour you are triggering: 
b [line] [condition]
    Set a breakpoint before the given line.  If a condition is
    specified, it's evaluated each time the statement is
    reached: a breakpoint is taken only if the condition is
    true.  Breakpoints may only be set on lines that begin an
    executable statement.  Conditions don't use "if":

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That is, you are setting a break point at the current line (because you specify no line) if $mysubref is true.
--
A math joke: r = | |csc(θ)|+|sec(θ)| |-| |csc(θ)|-|sec(θ)| |

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Re^2: how to set a breakpoint by a code reference
by Matq (Initiate) on Nov 19, 2013 at 01:43 UTC
    Here is the output document, 
    C:\Users>perl -d -e 0

Loading DB routines from perl5db.pl version 1.37
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(-e:1):   0

  DB<1> h b
b        Sets breakpoint on current line)
b [line] [condition]
        Set breakpoint; line defaults to the current execution line;
        condition breaks if it evaluates to true, defaults to '1'.
b subname [condition]
        Set breakpoint at first line of subroutine.
b $var        Set breakpoint at first line of subroutine referenced by
+ $var.
b load filename Set breakpoint on 'require'ing the given file.
b postpone subname [condition]
        Set breakpoint at first line of subroutine after
        it is compiled.
b compile subname
        Stop after the subroutine is compiled.

  DB<2> q

C:\Users>perl -v

This is perl 5, version 16, subversion 3 (v5.16.3) built for MSWin32-x
+86-multi-t
hread
(with 1 registered patch, see perl -V for more detail)

Copyright 1987-2012, Larry Wall

Binary build 1603 [296746] provided by ActiveState http://www.ActiveSt
+ate.com
Built Mar 13 2013 11:29:21

Perl may be copied only under the terms of either the Artistic License
+ or the
GNU General Public License, which may be found in the Perl 5 source ki
+t.

Complete documentation for Perl, including FAQ lists, should be found 
+on
this system using "man perl" or "perldoc perl".  If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.

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[reply]
[d/l]
      Interesting; that doesn't match perldoc perldebug.
      --
      A math joke: r = | |csc(θ)|+|sec(θ)| |-| |csc(θ)|-|sec(θ)| |
[reply]
        > Interesting; that doesn't match perldoc perldebug.

        perldebug : 

        - b subname [condition]

Set a breakpoint before the first line of the named subroutine. subnam
+e may be a variable containing a *code reference* (in this case condi
+tion is not supported).

        [download]

        Cheers Rolf

        ( addicted to the Perl Programming Language)

[reply]
[d/l]

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