c++/4524: member of const instance can be modifies via non-const pointer to member

c++/4524: member of const instance can be modifies via non-const pointer to member

[philipp.bachmann]

>Number:         4524
>Category:       c++
>Synopsis:       member of const instance can be modifies via non-const pointer to member
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 10 10:06:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Philipp Bachmann
>Release:        g++ 2.95.3
>Organization:
>Environment:
Sun Solaris 7 SPARC
>Description:
A non-const pointer to a member may be constructed such that even members of const  instances can be modified without explicitly casting away "const".

Though B. Stroustrup's C++-book is quite sparse concerning this specific topic and I don't have a copy of the C++-standard, I think that this is illegal.

Sun Workshop / Forte C++ 6 U 1 doesn't allow this. I don't have further compilers at hand to check on their behaviour...
>How-To-Repeat:
Compile with the definition of "BUG0" (line 13) commented in. Just run the resulting binary.
>Fix:
n.a.
>Release-Note:
>Audit-Trail:
>Unformatted:
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Re: c++/4524: member of const instance can be modifies via non-const pointer to member

[lerdsuwa]

Synopsis: member of const instance can be modifies via non-const pointer to member

State-Changed-From-To: open->closed
State-Changed-By: lerdsuwa
State-Changed-When: Mon Oct 22 09:49:56 2001
State-Changed-Why:
    Fixed in the main trunk (future gcc 3.1).

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=4524&database=gcc