6e63438a0d
This fixes a dangling-reference issue with views::split and other multi-argument
adaptors that may take its extra arguments by reference.
When creating the _RangeAdaptorClosure in _RangeAdaptor::operator(), we
currently capture all provided arguments by value. When we then use the
_RangeAdaptorClosure and call it with a range, as in e.g.
v = views::split(p)(range),
we forward the range and the captures to the underlying adaptor routine. But
then when the temporary _RangeAdaptorClosure goes out of scope, the by-value
captures get destroyed and the references to these captures in the resulting view
become dangling.
This patch fixes this problem by capturing lvalue references by reference in
_RangeAdaptorClosure::operator(), and then forwarding the captures appropriately
to the underlying adaptor routine.
libstdc++-v3/ChangeLog:
* include/std/ranges (views::__adaptor::__maybe_refwrap): New utility
function.
(views::__adaptor::_RangeAdaptor::operator()): Add comments. Use
__maybe_refwrap to capture lvalue references by reference, and then use
unwrap_reference_t to forward the by-reference captures as references.
* testsuite/std/ranges/adaptors/split.cc: Augment test.
* testsuite/std/ranges/adaptors/split_neg.cc: New test.
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| config | ||
| doc | ||
| include | ||
| libsupc++ | ||
| po | ||
| python | ||
| scripts | ||
| src | ||
| testsuite | ||
| acinclude.m4 | ||
| aclocal.m4 | ||
| ChangeLog | ||
| ChangeLog-1998 | ||
| ChangeLog-1999 | ||
| ChangeLog-2000 | ||
| ChangeLog-2001 | ||
| ChangeLog-2002 | ||
| ChangeLog-2003 | ||
| ChangeLog-2004 | ||
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| ChangeLog-2012 | ||
| ChangeLog-2013 | ||
| ChangeLog-2014 | ||
| ChangeLog-2015 | ||
| ChangeLog-2016 | ||
| ChangeLog-2017 | ||
| ChangeLog-2018 | ||
| ChangeLog-2019 | ||
| config.h.in | ||
| configure | ||
| configure.ac | ||
| configure.host | ||
| crossconfig.m4 | ||
| fragment.am | ||
| linkage.m4 | ||
| Makefile.am | ||
| Makefile.in | ||
| README | ||
file: libstdc++-v3/README New users may wish to point their web browsers to the file index.html in the 'doc/html' subdirectory. It contains brief building instructions and notes on how to configure the library in interesting ways.