https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97362
Bug ID: 97362
Summary: __deref in <functional> in debug mode clashes with
Windows SDK internal macro
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: frankhb1989 at gmail dot com
Target Milestone: ---
Case:
#include <windows.h>
#include <functional>
int main()
{}
/tmp $ g++ -D_GLIBCXX_DEBUG a.cc
In file included from F:/msys64/mingw64/include/c++/10.2.0/debug/debug.h:133,
from
F:/msys64/mingw64/include/c++/10.2.0/bits/stl_algobase.h:69,
from F:/msys64/mingw64/include/c++/10.2.0/array:40,
from F:/msys64/mingw64/include/c++/10.2.0/tuple:39,
from F:/msys64/mingw64/include/c++/10.2.0/functional:54,
from a.cc:2:
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:424:15: error: expected
unqualified-id before ')' token
424 | __deref();
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:34: error: expected
primary-expression before '<' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:38: error: expected
primary-expression before '>' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:40: error: expected
primary-expression before ')' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:51: error: expected
primary-expression before '<' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:55: error: expected
primary-expression before '>' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:427:57: error: expected
primary-expression before ')' token
427 | typename = decltype(__deref<_It>() < __deref<_It>())>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:42: error: expected
primary-expression before '<' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:46: error: expected
primary-expression before '>' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:48: error: expected
primary-expression before ')' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:58: error: expected
primary-expression before '<' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:62: error: expected
primary-expression before '>' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
| ^
F:/msys64/mingw64/include/c++/10.2.0/debug/functions.h:441:64: error: expected
primary-expression before ')' token
441 | = decltype(std::declval<_Pred>()(__deref<_It>(), __deref<_It>()))>
This is reproducible with MSYS2's {i686, x86_64}-w64-mingw32-g++. Note it
compiles without -D_GLIBCXX_DEBUG.
The offending `__deref` is from WinSDK header <sal.h> (also available in
mingw-w64 for compatibility). As a system header, it is legitimate to have
reserved identifiers. Although the workaround is simple (by #undef, since
<specstrings_undef.h> is not available in mingw-w64 yet), it is still annoying
and confusing. It seems a quick workaround by avoiding using `__deref` here is
more appropriate.
