https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97719
Bug ID: 97719
Summary: "Implement C++20 features for <sstream>" changed
behavior of istreambuf_iterator
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: rodgertq at gcc dot gnu.org
Target Milestone: ---
from mailing list -
On 07/10/2020 18:55, Thomas Rodgers wrote:
From: Thomas Rodgers <trodg...@redhat.com>
New ctors and ::view() accessor for -
* basic_stingbuf
* basic_istringstream
* basic_ostringstream
* basic_stringstreamm
New ::get_allocator() accessor for basic_stringbuf.
I found that this
<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=a0e4d7b44c544c84cffc7ff9c64b6f1af14fb08d>
"libstdc++: Implement C++20 features for <sstream>" changed the behavior of
$ cat test.cc
#include <iostream>
#include <iterator>
#include <sstream>
int main() {
std::stringstream s("a");
std::istreambuf_iterator<char> i(s);
if (i != std::istreambuf_iterator<char>()) std::cout << *i << '\n';
}
$ g++ -std=c++20 test.cc
$ ./a.out
from printing "a" to printing nothing. (The `i != ...` comparison appears to
change i from pointing at "a" to pointing to null, and returns false.)
I ran into this when building LibreOffice, and I hope test.cc is a faithfully
minimized reproducer. However, I know little about std::istreambuf_iterator,
so it may well be that the code isn't even valid.
