* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
@ 2009-02-09 7:39 ` fang at csl dot cornell dot edu
2009-02-09 9:53 ` paolo dot carlini at oracle dot com
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From: fang at csl dot cornell dot edu @ 2009-02-09 7:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from fang at csl dot cornell dot edu 2009-02-09 07:39 -------
also "Fails": 4.2.4
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
2009-02-09 7:39 ` [Bug libstdc++/39136] " fang at csl dot cornell dot edu
@ 2009-02-09 9:53 ` paolo dot carlini at oracle dot com
2009-02-09 15:59 ` fang at csl dot cornell dot edu
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From: paolo dot carlini at oracle dot com @ 2009-02-09 9:53 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from paolo dot carlini at oracle dot com 2009-02-09 09:53 -------
(In reply to comment #0)
> I'm not sure if this is valid code. However, the standard seems to indicate
> that resize(size_type), is a required member function (or at least interface)
> of std::vector.
Which standard? To be clear, in the current one, the function is
resize(size_type sz, T c = T()).
Otherwise, the C++0x overloads require concepts (and I think we also have an
open PR about that)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
2009-02-09 7:39 ` [Bug libstdc++/39136] " fang at csl dot cornell dot edu
2009-02-09 9:53 ` paolo dot carlini at oracle dot com
@ 2009-02-09 15:59 ` fang at csl dot cornell dot edu
2009-02-09 16:11 ` paolo dot carlini at oracle dot com
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From: fang at csl dot cornell dot edu @ 2009-02-09 15:59 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from fang at csl dot cornell dot edu 2009-02-09 15:58 -------
Subject: Re: std::mem_fun_ref fails to accept a member
function whose second argument with default value
> ------- Comment #2 from paolo dot carlini at oracle dot com 2009-02-09 09:53 -------
> (In reply to comment #0)
>> I'm not sure if this is valid code. However, the standard seems to indicate
>> that resize(size_type), is a required member function (or at least interface)
>> of std::vector.
>
> Which standard? To be clear, in the current one, the function is
> resize(size_type sz, T c = T()).
I'm looking at the current draft, n2798.
23.2.6.2/10-11 [vector.capacity]
which lists both forms of resize().
Yes, libstdc++ covers both by using the trailing default argument, but I
still can't pass it to mem_fun/mem_fun_ref.
Compilation still fails with both -std=c++0x and -std=c++98 with the
above test case. (Test case contains a stray line "Test case:" from
mis-pasting, my bad.)
> Otherwise, the C++0x overloads require concepts (and I think we also have an
> open PR about that)
Got a PR reference handy?
Fang
David Fang
http://www.csl.cornell.edu/~fang/
http://www.achronix.com/
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (2 preceding siblings ...)
2009-02-09 15:59 ` fang at csl dot cornell dot edu
@ 2009-02-09 16:11 ` paolo dot carlini at oracle dot com
2009-02-09 16:47 ` paolo dot carlini at oracle dot com
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From: paolo dot carlini at oracle dot com @ 2009-02-09 16:11 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from paolo dot carlini at oracle dot com 2009-02-09 16:11 -------
(In reply to comment #3)
> I'm looking at the current draft, n2798.
> 23.2.6.2/10-11 [vector.capacity]
> which lists both forms of resize().
> Yes, libstdc++ covers both by using the trailing default argument, but I
> still can't pass it to mem_fun/mem_fun_ref.
To be clear again: the current draft is not relevant here, because we are *not*
implementing it. Concepts are needed, see PR 32618.
Thus, since we are strictly following the standard as far as std::vector is
concerned, I have troubles believing that the implementation of mem_fun_ref is
at fault in any sense, that is really old code, and following rather directly
from the specs. Either a C++ issue, or not a bug. Please double check.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (3 preceding siblings ...)
2009-02-09 16:11 ` paolo dot carlini at oracle dot com
@ 2009-02-09 16:47 ` paolo dot carlini at oracle dot com
2009-02-09 17:21 ` fang at csl dot cornell dot edu
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From: paolo dot carlini at oracle dot com @ 2009-02-09 16:47 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from paolo dot carlini at oracle dot com 2009-02-09 16:47 -------
Your snippet boils down to this, which is clearly invalid:
struct vector
{
void resize(long unsigned int, int = 0);
};
template<typename _Ret, typename _Tp, typename _Arg>
void
mem_fun_ref(_Ret (_Tp::*__f)(_Arg));
void
test() {
mem_fun_ref(&vector::resize);
}
--
paolo dot carlini at oracle dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (4 preceding siblings ...)
2009-02-09 16:47 ` paolo dot carlini at oracle dot com
@ 2009-02-09 17:21 ` fang at csl dot cornell dot edu
2009-02-09 17:26 ` paolo dot carlini at oracle dot com
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From: fang at csl dot cornell dot edu @ 2009-02-09 17:21 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from fang at csl dot cornell dot edu 2009-02-09 17:21 -------
Subject: Re: std::mem_fun_ref fails to accept a member
function whose second argument with default value
> ------- Comment #5 from paolo dot carlini at oracle dot com 2009-02-09 16:47 -------
> Your snippet boils down to this, which is clearly invalid:
>
> struct vector
> {
> void resize(long unsigned int, int = 0);
> };
>
> template<typename _Ret, typename _Tp, typename _Arg>
> void
> mem_fun_ref(_Ret (_Tp::*__f)(_Arg));
>
> void
> test() {
> mem_fun_ref(&vector::resize);
> }
Fair enough, that's what I wanted to know.
I suppose mem_fun_ref(&vector::resize) just *happened* to be accepted in
earlier versions of libstdc++, when it was never required to do so.
The following declaration was what allowed it to do so.
// 4.0.1 <bits/stl_vector.h>
// class vector {
void
resize(size_type __new_size)
{ resize(__new_size, value_type()); }
// };
Was there a compelling reason to remove it in favor of the unified
::resize(size_type, const value_type& t = T)?
Anyhow, thanks for the feedback!
Fang
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (5 preceding siblings ...)
2009-02-09 17:21 ` fang at csl dot cornell dot edu
@ 2009-02-09 17:26 ` paolo dot carlini at oracle dot com
2009-02-09 17:54 ` fang at csl dot cornell dot edu
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From: paolo dot carlini at oracle dot com @ 2009-02-09 17:26 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from paolo dot carlini at oracle dot com 2009-02-09 17:26 -------
(In reply to comment #6)
> Was there a compelling reason to remove it in favor of the unified
> ::resize(size_type, const value_type& t = T)?
Yes, is non-conforming! I thought it was clear at this point... Just try to
instantiate that version of std::vector with a non-DefaultConstructible Tp!
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (6 preceding siblings ...)
2009-02-09 17:26 ` paolo dot carlini at oracle dot com
@ 2009-02-09 17:54 ` fang at csl dot cornell dot edu
2009-02-09 17:59 ` paolo dot carlini at oracle dot com
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From: fang at csl dot cornell dot edu @ 2009-02-09 17:54 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from fang at csl dot cornell dot edu 2009-02-09 17:54 -------
Subject: Re: std::mem_fun_ref fails to accept a member
function whose second argument with default value
> ------- Comment #7 from paolo dot carlini at oracle dot com 2009-02-09 17:26 -------
> (In reply to comment #6)
>> Was there a compelling reason to remove it in favor of the unified
>> ::resize(size_type, const value_type& t = T)?
>
> Yes, is non-conforming! I thought it was clear at this point... Just try to
> instantiate that version of std::vector with a non-DefaultConstructible Tp!
At no point was vector<Tp>::resize() ever instantiatable with a
non-DefaultConstructible Tp, even with the old size_type-only member
function. It would have failed on value_type() in the definition body.
That doesn't make it any less conforming, does it?
The default-tail-argument version of ::resize() (with = Tp()) just fails
at the prototype in a concept-way, rather than through body instantiation.
Is that the critical difference?
Fang
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (7 preceding siblings ...)
2009-02-09 17:54 ` fang at csl dot cornell dot edu
@ 2009-02-09 17:59 ` paolo dot carlini at oracle dot com
2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
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From: paolo dot carlini at oracle dot com @ 2009-02-09 17:59 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from paolo dot carlini at oracle dot com 2009-02-09 17:59 -------
(In reply to comment #8)
> At no point was vector<Tp>::resize() ever instantiatable with a
> non-DefaultConstructible Tp, even with the old size_type-only member
> function. It would have failed on value_type() in the definition body.
> That doesn't make it any less conforming, does it?
I do not understand what you are saying: a std::vector strictly following the
current, C++03 specifications, can be explicitly instantiated for a
non-DefaultConstructible Tp. And indeed, this is what happens with current v3,
and was *not* happening back in the 4.0 time.
In C++0x, thanks to Concepts, that will be also true, it will be possible to
explicitly instantiate std::vector for a non-DefaultConstructible Tp and, plus,
it will possible to have 2 separate, optimized, overloads.
I don't see any other option.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
` (8 preceding siblings ...)
2009-02-09 17:59 ` paolo dot carlini at oracle dot com
@ 2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
10 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2009-02-10 22:03 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from pinskia at gcc dot gnu dot org 2009-02-10 22:03 -------
Reopening to ...
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|INVALID |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug libstdc++/39136] std::mem_fun_ref fails to accept a member function whose second argument with default value
2009-02-09 6:50 [Bug libstdc++/39136] New: std::mem_fun_ref fails to accept a member function whose second argument with default value fang at csl dot cornell dot edu
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2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
@ 2009-02-10 22:03 ` pinskia at gcc dot gnu dot org
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From: pinskia at gcc dot gnu dot org @ 2009-02-10 22:03 UTC (permalink / raw)
To: gcc-bugs
------- Comment #11 from pinskia at gcc dot gnu dot org 2009-02-10 22:03 -------
Mark this as a dup of bug 37088.
*** This bug has been marked as a duplicate of 37088 ***
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39136
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