Package: g++-mingw-w64-x86-64
Version: 8.3.0-6+21.3~deb10u1
Severity: normal
Tags: patch
Dear Maintainer,
I had some issues linking an application being built as C++14 and using the
std::experimental::filesystem -
it mentioned unresolved "fs_err_concat" symbols. When researching it, I
discovered this page,
which explained the exact message and contained a patch.
https://patches-gcc.linaro.org/patch/12753/#22525
Apparently a change elsewhere removed a symbol that the experimental filesystem
support was still using,
and my testing suggests that the Debian package lacks this patch.
I've added the patch to the Buster package here:
https://salsa.debian.org/mingw-w64-team/gcc-mingw-w64/merge_requests/1
and I've confirmed that it applies and starts building - I didn't have the
storage space to run the build
to completion locally.
The minimized test file is attached: the comment explains how to build and link
as either C++17
(using std::filesystem - this works) or C++14 (using
std::experimental::filesystem, produces the error)
I suspect newer upstream (e.g. not Buster) already contains the patch, but this
test file should make it easy to check.
The error message is:
/usr/bin/x86_64-w64-mingw32-ld:
/usr/lib/gcc/x86_64-w64-mingw32/8.3-win32/libstdc++fs.a(path.o):(.text$_ZNSt12experimental10filesystem2v17__cxx1116filesystem_error11_M_gen_whatEv+0x639):
undefined reference to
`std::filesystem::fs_err_concat(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&)'
Thank you!
Ryan
-- System Information:
Debian Release: 10.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-debug'), (500, 'stable'),
(1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 5.3.0-0.bpo.2-amd64 (SMP w/16 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8),
LANGUAGE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages g++-mingw-w64-x86-64 depends on:
ii gcc-mingw-w64-base 8.3.0-6+21.3~deb10u1
ii gcc-mingw-w64-x86-64 8.3.0-6+21.3~deb10u1
ii libc6 2.28-10
ii libgcc1 1:8.3.0-6
ii libgmp10 2:6.1.2+dfsg-4
ii libisl19 0.20-2
ii libmpc3 1.1.0-1
ii libmpfr6 4.0.2-1
ii libstdc++6 8.3.0-6
ii zlib1g 1:1.2.11.dfsg-1
g++-mingw-w64-x86-64 recommends no packages.
Versions of packages g++-mingw-w64-x86-64 suggests:
pn gcc-8-locales <none>
-- no debconf information
/*
This builds and links:
$ x86_64-w64-mingw32-g++ -std=c++17 demo.cpp -o demo17.o -Wl,--no-undefined
-lstdc++fs
This fails to link:
$ x86_64-w64-mingw32-g++ -std=c++14 demo.cpp -o demo14.o -Wl,--no-undefined
-lstdc++fs
/usr/bin/x86_64-w64-mingw32-ld:
/usr/lib/gcc/x86_64-w64-mingw32/8.3-win32/libstdc++fs.a(path.o):(.text$_ZNSt12experimental10filesystem2v17__cxx1116filesystem_error11_M_gen_whatEv+0x639):
undefined reference to
`std::filesystem::fs_err_concat(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&)'
*/
// If the C++ macro is set to the version containing C++17, it must support
// the final C++17 package
#if __cplusplus >= 201703L
#include <filesystem>
namespace fs = std::filesystem;
#else
#include <experimental/filesystem>
namespace fs = std::experimental::filesystem;
#endif
bool is_reg_file(const std::string &path) { return fs::is_regular_file(path); }
int main() {
(void)is_reg_file("/etc/os-release");
return 0;
}
