http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57207
Bug #: 57207
Summary: Incorrect lifetime of const references bound to
temporary
Classification: Unclassified
Product: gcc
Version: 4.7.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: [email protected]
ReportedBy: [email protected]
Created attachment 30053
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30053
main.ii generated via --save-temps
Here the programme:
#include <iostream>
struct TMyStruct
{ };
struct TByteArrayList
{
TByteArrayList(const TByteArrayList &)
{ i = 12; std::cout << "copy ctor " << this << std::endl; }
TByteArrayList &operator=(const TByteArrayList &)
{ std::cout << "operator = " << this << std::endl; return *this; }
TByteArrayList()
{ i = 12; std::cout << "ctor " << this << std::endl; }
~TByteArrayList()
{ std::cout << "dtor " << this << std::endl; }
TByteArrayList &operator<<(const TMyStruct &)
{ std::cout << "<< " << this << std::endl; return *this; }
int i;
};
int main()
{
const TByteArrayList &List = TByteArrayList() << TMyStruct();
std::cout << "Here some use of List: " << List.i << " address " << &List
<< std::endl;
return 0;
}
And here its output:
ctor 0x7fff22f27350
<< 0x7fff22f27350
dtor 0x7fff22f27350
Here some use of List: 12 address 0x7fff22f27350
Why dtor of List called right after List is created in this line
const TByteArrayList &List = TByteArrayList() << TMyStruct();
Why const reference to temporary object (List) does not prolong life time of
temporary object (TByteArrayList() << TMyStruct())?
Seems it is a bug.
//===============================================
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.3-1ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.7 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin
--with-system-zlib --enable-objc-gc --with-cloog --enable-cloog-backend=ppl
--disable-cloog-version-check --disable-ppl-version-check --enable-multiarch
--disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1)
