Sorry for previous patch, I was too focus on _GLIBCXX_DEBUG mode and
tend to forget that template methods can be exported.
Let's try with this less enthusiast version then.
I've split the patch, so the subject change. The small _GLIBCXX_DEBUG
parts left will come in a future patch, not implying new symbols thought.
For now I think just adding _RequireInputIte and remove in C++11 useless
methods is fine.
libstdc++: Decorate COW string methods with std::_RequireInputIte
Add the std::_RequireInputIter constraints on members taking template
iterator range to avoid the "do the right thing" ambiguity.
Thanks to this requirement remove, in post-C++11, associated
dispatch methods.
libstdc++v3/ChangeLog:
* include/bits/cow_string.h
(basic_string(_InputIterator, _InputIterator, const _Alloc&):
Add std::_RequireInputIter constraint and
__glibcxx_requires_valid_constructor_range check.
(basic_string::append(_InputIte, _InputIte): Add
std::_RequireInputIter
constraint.
(basic_string::assign(_InputIte, _InputIte): Likewise.
(basic_string::insert(iterator, _InputIte, _InputIte)):
Likewise.
(basic_string::replace(iterator, iterator, _InputIte,
_InputIte)): Likewise.
[__cplusplus < 201103L](basic_string::_M_replace_dispatch
(iterator, iterator, _Integer, _Integer, __true_type)): Remove.
[__cplusplus < 201103L](basic_string::_S_construct_aux):
Remove.
[__cplusplus < 201103L](basic_string::_S_construct_aux_2):
Remove.
(basic_string::_S_construct): Adapt.
Tested under Linux x86_64 testsuite/21_strings/* C++98 & C++23 including
abi check.
Ok to commit ?
François
On 7/21/26 13:19, Jonathan Wakely wrote:
On Tue, 21 Jul 2026 at 07:43, Jonathan Wakely<[email protected]> wrote:
On Tue, 21 Jul 2026 at 05:57, François Dumont<[email protected]> wrote:
Here is the new commit message:
libstdc++: [_GLIBCXX_DEBUG] Improve COW basic_string checks
Put the __glibcxx_requires_valid_range checks at public member level
so that diagnostics are giving directly the culprit member name.
Add thestd::_RequireInputIter constraints on members taking template
iterator range to avoid the "do the right thing" ambiguity.
libstdc++v3/ChangeLog:
* include/bits/cow_string.h
(basic_string::_M_replace): New.
(basic_string(_InputIterator, _InputIterator, const _Alloc&):
Addstd::_RequireInputIter constraint and
__glibcxx_requires_valid_constructor_range check.
(basic_string::append(_InputIte, _InputIte): Add
std::_RequireInputIter
constraint and __glibcxx_requires_valid_range check. Call
_M_replace.
(basic_string::assign(_InputIte, _InputIte): Likewise.
(basic_string::insert(iterator, _InputIte, _InputIte)):
Likewise.
(basic_string::replace(iterator, iterator, _InputIte,
_InputIte)): Likewise.
[__cplusplus >= 201103L](basic_string::_S_construct): New.
(basic_string::_M_replace_dispatch(iterator, iterator,
_InputIte, _InputIte,
__false_type)): Remove __glibcxx_requires_valid_range check.
* include/debug/debug.h
(__glibcxx_requires_valid_constructor_range): New.
On 7/6/26 22:42, Jonathan Wakely wrote:
On Mon, 15 Jun 2026 at 07:07 +0200, François Dumont wrote:
Hi
libstdc++: [_GLIBCXX_DEBUG] Improve COW basic_string checks
Put the __glibcxx_requires_valid_range checks at public member level
so that diagnostics are giving directly the invoked member name.
Add thestd::_RequireInputIter constraints on members taking
template
iterator range to avoid the "do the right thing" ambiguity
without the help of __is_integer.
libstdc++v3/ChangeLog:
* include/bits/cow_string.h
(basic_string::_M_replace): New.
(basic_string(_InputIterator, _InputIterator, const
_Alloc&): Add
std::_RequireInputIter constraint and
__glibcxx_requires_valid_constructor_range
Please fix the line-wrapping here. Try to keep the lines to < 72
characters so that when indented by 'git log' they fit below 80.
check.
(basic_string::append(_InputIte, _InputIte): Add
std::_RequireInputIter
constraint and __glibcxx_requires_valid_range check. Call
_M_replace.
(basic_string::assign(_InputIte, _InputIte): Likewise.
(basic_string::insert(iterator, _InputIte, _InputIte)):
Likewise.
(basic_string::replace(iterator, iterator, _InputIte,
_InputIte)): Likewise.
[__cplusplus >= 201103L](basic_string::_S_construct): New.
(basic_string::_M_replace_dispatch(iterator, iterator,
_InputIte, _InputIte,
__false_type)): Remove __glibcxx_requires_valid_range check.
* include/debug/debug.h
(__glibcxx_requires_valid_constructor_range): New.
Tested under Linux x86_64 with _GLIBCXX_USE_CXX11_ABI=0 and
_GLIBCXX_DEBUG.
Did you test C++98 as well as the default -std modes?
I hadn't but now did, ex:
In function:
std::basic_string<_CharT, _Traits, _Alloc>&std::basic_string<_CharT,
_Traits, _Alloc>::append(_InputIterator, _InputIterator) [with
_InputIterator = gnu_debug::_Safe_iterator<gnu_cxx::
normal_iterator<char*,std::vector<char,std::allocator<char> > >,
std::
debug::vector<char>,std::random_access_iterator_tag>; _CharT = char;
_Traits =std::char_traits<char>; _Alloc =std::allocator<char>]
Error: function requires a valid iterator range [first, last).
Objects involved in the operation:
iterator "first" @ 0x7ffc9027e5a0 {
type = gnu_cxx::normal_iterator<char*,std::vector<char,
std::allocator<char> > > (mutable iterator);
state = dereferenceable;
references sequence with type 'std::debug::vector<char,
std::allocator<char> >' @ 0x7ffc9027e750
}
iterator "last" @ 0x7ffc9027e600 {
type = gnu_cxx::normal_iterator<char*,std::vector<char,
std::allocator<char> > > (mutable iterator);
state = dereferenceable;
references sequence with type 'std::debug::vector<char,
std::allocator<char> >' @ 0x7ffc9027e750
}
XFAIL: 21_strings/basic_string/debug/append_neg.cc -std=gnu++98
execution test
Doesn't this require new symbols to be exported by the linker script?
I don't think so. Maybe you had in mind the
__gnu_debug::__check_valid_range but that's a template function
implemented inline.
You've added a new member function, basic_string::_M_replace. Why
doesn't that need to be exported from the shared library?
Why don't the changes to the signature of basic_string::assign and
basic_string::append change the exported symbols?
As expected, 'make check-abi' fails:
Running /home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/libstdc++-abi/abi.exp
...
FAIL: libstdc++-abi/abi_check
=== libstdc++ Summary ===
# of unexpected failures 1
Ok to commit ?
Definitely not.
diff --git a/libstdc++-v3/include/bits/cow_string.h
b/libstdc++-v3/include/bits/cow_string.h
index 0f1a2e082d0..a3f9195c098 100644
--- a/libstdc++-v3/include/bits/cow_string.h
+++ b/libstdc++-v3/include/bits/cow_string.h
@@ -721,7 +721,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @param __end End of range.
* @param __a Allocator to use (default is default allocator).
*/
- template<class _InputIterator>
+#if __cplusplus >= 201103L
+ template<typename _InputIterator,
+ typename = std::_RequireInputIter<_InputIterator>>
+#else
+ template<typename _InputIterator>
+#endif
basic_string(_InputIterator __beg, _InputIterator __end,
const _Alloc& __a = _Alloc())
: _M_dataplus(_S_construct(__beg, __end, __a), __a)
@@ -1391,7 +1396,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*
* Appends characters in the range [__first,__last) to this string.
*/
- template<class _InputIterator>
+#if __cplusplus >= 201103L
+ template<typename _InputIterator,
+ typename = std::_RequireInputIter<_InputIterator>>
+#else
+ template<typename _InputIterator>
+#endif
basic_string&
append(_InputIterator __first, _InputIterator __last)
{ return this->replace(_M_iend(), _M_iend(), __first, __last); }
@@ -1551,7 +1561,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*
* Sets value of string to characters in the range [__first,__last).
*/
- template<class _InputIterator>
+#if __cplusplus >= 201103L
+ template<typename _InputIterator,
+ typename = std::_RequireInputIter<_InputIterator>>
+#else
+ template<typename _InputIterator>
+#endif
basic_string&
assign(_InputIterator __first, _InputIterator __last)
{ return this->replace(_M_ibegin(), _M_iend(), __first, __last); }
@@ -1657,7 +1672,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* length_error is thrown. The value of the string doesn't
* change if an error is thrown.
*/
- template<class _InputIterator>
+#if __cplusplus >= 201103L
+ template<typename _InputIterator,
+ typename = std::_RequireInputIter<_InputIterator>>
+#else
+ template<typename _InputIterator>
+#endif
void
insert(iterator __p, _InputIterator __beg, _InputIterator __end)
{ this->replace(__p, __p, __beg, __end); }
@@ -2143,14 +2163,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* The value of the string doesn't change if an error is
* thrown.
*/
- template<class _InputIterator>
+#if __cplusplus >= 201103L
+ template<typename _InputIterator,
+ typename = std::_RequireInputIter<_InputIterator>>
+#else
+ template<typename _InputIterator>
+#endif
basic_string&
replace(iterator __i1, iterator __i2,
_InputIterator __k1, _InputIterator __k2)
{
_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
&& __i2 <= _M_iend());
+#if __cplusplus >= 201103L
+ typedef std::__false_type _Integral;
+#else
typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+#endif
return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
}
@@ -2295,11 +2324,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif // C++17
private:
+#if __cplusplus < 201103L
template<class _Integer>
basic_string&
_M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n,
_Integer __val, __true_type)
{ return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); }
+#endif
template<class _InputIterator>
basic_string&
@@ -2314,6 +2345,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
size_type __n2);
+#if __cplusplus < 201103L
// _S_construct_aux is used to implement the 21.3.1 para 15 which
// requires special behaviour if _InIter is an integral type
template<class _InIterator>
@@ -2337,13 +2369,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static _CharT*
_S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a)
{ return _S_construct(__req, __c, __a); }
+#endif
template<class _InIterator>
static _CharT*
_S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a)
{
+#if __cplusplus < 201103L
typedef typename std::__is_integer<_InIterator>::__type _Integral;
return _S_construct_aux(__beg, __end, __a, _Integral());
+#else
+ return _S_construct(__beg, __end, __a,
+ std::__iterator_category(__beg));
+#endif
}
// For Input Iterators, used in istreambuf_iterators, etc.
