https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71955
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |marxin at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Also p1 and p2 contain undefined behavior, that's reason why the program can't
be compiled w/ -fpermissive.
Running p1 with valgind shows:
==1728== Conditional jump or move depends on uninitialised value(s)
==1728== at 0x4F5D323: std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char>
>::_M_assign(std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&) (in /usr/lib64/libstdc++.so.6.0.22)
==1728== by 0x4F5D6E8: std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char>
>::operator=(std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&) (in /usr/lib64/libstdc++.so.6.0.22)
==1728== by 0x400D85:
SampleStringClass::SampleStringClass(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&) (in
/home/marxin/Downloads/gcc-question/a.out)
==1728== by 0x400CA5: main (in /home/marxin/Downloads/gcc-question/a.out)
==1728==
==1728== Use of uninitialised value of size 8
==1728== at 0x4EF12C0: std::basic_ostream<char, std::char_traits<char> >&
std::operator<< <char, std::char_traits<char>, std::allocator<char>
>(std::basic_ostream<char, std::char_traits<char> >&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&) (in /usr/lib64/libstdc++.so.6.0.22)
==1728== by 0x400DA9: SampleStringClass::show() (in
/home/marxin/Downloads/gcc-question/a.out)
==1728== by 0x400CB1: main (in /home/marxin/Downloads/gcc-question/a.out)
==1728==
Anand Apparao Kulkarni
==1728== Use of uninitialised value of size 8
==1728== at 0x4EF12C0: std::basic_ostream<char, std::char_traits<char> >&
std::operator<< <char, std::char_traits<char>, std::allocator<char>
>(std::basic_ostream<char, std::char_traits<char> >&,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&) (in /usr/lib64/libstdc++.so.6.0.22)
==1728== by 0x400DA9: SampleStringClass::show() (in
/home/marxin/Downloads/gcc-question/a.out)
==1728== by 0x400CBD: main (in /home/marxin/Downloads/gcc-question/a.out)
==1728==
Anand Apparao Kulkarni
Thus I would suggest following patch to your source code:
--- p1.backup 2016-07-21 11:22:20.651299644 +0200
+++ p1.cpp 2016-07-21 11:23:37.128793125 +0200
@@ -5,11 +5,10 @@
class SampleStringClass {
private:
- std::string& ref;
+ const std::string& ref;
public:
- SampleStringClass(const std::string& arg)
+ SampleStringClass(const std::string& arg): ref (arg)
{
- ref=arg;
}
void show()
{
@@ -19,11 +18,10 @@
class SampleIntClass {
private:
- int& ref;
+ const int& ref;
public:
- SampleIntClass(const int& arg)
+ SampleIntClass(const int& arg): ref (arg)
{
- ref=arg;
}
void show()
{
