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I encountered this problem while doing my assignments. When you have a class B that inherits class A, and B initializes variables in A by calling the constructor of A in B's constructor, the variable that is supposed to be initialized in A's constructor remains uninitialized. This doesn't seem to happen if we create an object of class A, even though seemingly the only difference is the inheritance and constructor chain.
Here is a minimal example:
#include <iostream>
#include <string>
class A {
public:
A(std::string s)
: s_(s) {}
~A(){}
void Print() const {
std::cout << s_ + "123";
}
private:
const std::string& s_;
};
class B : public A {
public:
B(std::string s)
: A(s) {}
};
int main()
{
//A a = A("123");
//a.Print();
B b = B("123");
b.Print();
}
In Print(), you can remove the extra string literal. This way the issue is focused on the variable not being initialized. But with the extra literal, according to valgrind, a million bytes are still reachable. This seems very weird.
Valgrind without literal in Print():
g++ -c -g -std=c++17 -Wall -Wextra -pedantic main.cpp -o main.o
g++ main.o -o main
valgrind ./main
==22551== Memcheck, a memory error detector
==22551== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==22551== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==22551== Command: ./main
==22551==
==22551== error calling PR_SET_PTRACER, vgdb might block
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x4F4FA9A: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x545C928: fwrite (iofwrite.c:35)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x54689B4: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1226)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x5468A85: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1275)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x5468210: _IO_file_write##GLIBC_2.2.5 (fileops.c:1198)
==22551== by 0x5468B9E: new_do_write (fileops.c:457)
==22551== by 0x5468B9E: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1277)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Syscall param write(buf) contains uninitialised byte(s)
==22551== at 0x54ED264: write (write.c:27)
==22551== by 0x546822C: _IO_file_write##GLIBC_2.2.5 (fileops.c:1203)
==22551== by 0x5468B9E: new_do_write (fileops.c:457)
==22551== by 0x5468B9E: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1277)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Syscall param write(count) contains uninitialised byte(s)
==22551== at 0x54ED264: write (write.c:27)
==22551== by 0x546822C: _IO_file_write##GLIBC_2.2.5 (fileops.c:1203)
==22551== by 0x5468B9E: new_do_write (fileops.c:457)
==22551== by 0x5468B9E: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1277)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Syscall param write(buf) points to uninitialised byte(s)
==22551== at 0x54ED264: write (write.c:27)
==22551== by 0x546822C: _IO_file_write##GLIBC_2.2.5 (fileops.c:1203)
==22551== by 0x5468B9E: new_do_write (fileops.c:457)
==22551== by 0x5468B9E: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1277)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551== Address 0x1ffefff910 is on thread 1's stack
==22551== in frame #5, created by A::Print() const (main.cpp:14)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x5468BB0: new_do_write (fileops.c:458)
==22551== by 0x5468BB0: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1277)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x5468BEB: _IO_file_xsputn##GLIBC_2.2.5 (fileops.c:1279)
==22551== by 0x545C9E6: fwrite (iofwrite.c:39)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x545CA65: fwrite (iofwrite.c:45)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x545CA6A: fwrite (iofwrite.c:45)
==22551== by 0x4F4FB83: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551== Conditional jump or move depends on uninitialised value(s)
==22551== at 0x4F4FB91: std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.25)
==22551== by 0x109BAF: A::Print() const (main.cpp:15)
==22551== by 0x1099EB: main (main.cpp:32)
==22551==
==22551==
==22551== HEAP SUMMARY:
==22551== in use at exit: 0 bytes in 0 blocks
==22551== total heap usage: 2 allocs, 2 frees, 73,216 bytes allocated
==22551==
==22551== All heap blocks were freed -- no leaks are possible
==22551==
==22551== For counts of detected and suppressed errors, rerun with: -v
==22551== Use --track-origins=yes to see where uninitialised values come from
==22551== ERROR SUMMARY: 13 errors from 13 contexts (suppressed: 0 from 0)
Valgrind with literal in Print():
(I had to cut the middle out to fit into the character limit, the whole thing is here: https://pastebin.com/UQmB0mXj)
g++ -c -g -std=c++17 -Wall -Wextra -pedantic main.cpp -o main.o
g++ main.o -o main
valgrind ./main
==22561== Memcheck, a memory error detector
==22561== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==22561== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==22561== Command: ./main
==22561==
==22561== error calling PR_SET_PTRACER, vgdb might block
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x10AC50: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:217)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x10AD84: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_create(unsigned long&, unsigned long) (basic_string.tcc:137)
==22561== by 0x10AC69: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:219)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
...
had to cut here to fit into character limit
...
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x10A9F0: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:337)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x109DE1: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:348)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x4C366E6: memmove (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22561== by 0x109E05: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:350)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x4C36711: memmove (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22561== by 0x109E05: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:350)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Conditional jump or move depends on uninitialised value(s)
==22561== at 0x4C367EE: memmove (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22561== by 0x109E05: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:350)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561==
==22561== Invalid read of size 8
==22561== at 0x4C367EE: memmove (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22561== by 0x109E05: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:350)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561== Address 0x1fff001000 is not stack'd, malloc'd or (recently) free'd
==22561==
==22561==
==22561== Process terminating with default action of signal 11 (SIGSEGV)
==22561== Access not within mapped region at address 0x1FFF001000
==22561== at 0x4C367EE: memmove (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22561== by 0x109E05: std::char_traits<char>::copy(char*, char const*, unsigned long) (char_traits.h:350)
==22561== by 0x10AA1D: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) (basic_string.h:340)
==22561== by 0x10AED7: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char*, char*) (basic_string.h:382)
==22561== by 0x10ACB0: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forward_iterator_tag) (basic_string.tcc:225)
==22561== by 0x10A7DD: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char*>(char*, char*, std::__false_type) (basic_string.h:236)
==22561== by 0x10A472: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*) (basic_string.h:255)
==22561== by 0x10A15B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (basic_string.h:440)
==22561== by 0x10A05E: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char const*) (basic_string.h:5928)
==22561== by 0x109E66: A::Print() const (main.cpp:15)
==22561== by 0x109C8B: main (main.cpp:32)
==22561== If you believe this happened as a result of a stack
==22561== overflow in your program's main thread (unlikely but
==22561== possible), you can try to increase the size of the
==22561== main thread stack using the --main-stacksize= flag.
==22561== The main thread stack size used in this run was 8388608.
==22561==
==22561== HEAP SUMMARY:
==22561== in use at exit: 1,089,515 bytes in 1 blocks
==22561== total heap usage: 2 allocs, 1 frees, 1,162,219 bytes allocated
==22561==
==22561== LEAK SUMMARY:
==22561== definitely lost: 0 bytes in 0 blocks
==22561== indirectly lost: 0 bytes in 0 blocks
==22561== possibly lost: 0 bytes in 0 blocks
==22561== still reachable: 1,089,515 bytes in 1 blocks
==22561== suppressed: 0 bytes in 0 blocks
==22561== Rerun with --leak-check=full to see details of leaked memory
==22561==
==22561== For counts of detected and suppressed errors, rerun with: -v
==22561== Use --track-origins=yes to see where uninitialised values come from
==22561== ERROR SUMMARY: 197 errors from 12 contexts (suppressed: 0 from 0)
src.make:32: recipe for target 'valgrind-run' failed
make: *** [valgrind-run] Segmentation fault (core dumped)
My questions are:
Why does the compiler not give an error because of A's constructor? How can we set a reference with the value?
Why does this only give errors when there is inheritance involved?
Why does adding a literal in Print() have such a big effect? And why are a million bytes allocated because of this?
Why does the compiler not give an error because of A's constructor?
Presumably because A's constructor is well-formed, and thus the compiler must accept it in order to conform to the standard.
You are allowed to bind a reference to a local variable. The reference will be invalid after the constructor returns, but if the program never indirects through the reference after returning from the constructor, then that is technically no problem. It is not trivial for the compiler to prove that the program will do that (this problem is generally analogous to the halting problem).
A compiler does warn about it through:
warning: binding reference member 's_' to stack allocated parameter 's' [-Wdangling-field]
How can we set a reference with the value?
You have bound the reference to the local variable. It is unclear what you're trying to do, but probably you should not be using a reference member to achieve that.
Why ...
Why ...
Because behaviour of the program is undefined. Any change can affect the behaviour of the program in any way. The behaviour can even change without change to the program. Or it might not change. Nothing about the behaviour of the program is guaranteed.
I'm trying to install the mongo-c-driver and mongo-cxx-driver in a Docker image, but when I run my C++ program it throws a Segmentation fault. Any ideas? Valgrind says it's mongo's fault.
I have some IOT devices and in my own computer they run just fine.
I'm using:
ubuntu:focal as base image
mongo-c-driver version 1.16.2 (also tried with 1.17 and 1.15)
mongo-cxx-driver version 3.5 (also tried with 3.6)
MongoDB server version 4.2.8
g++ version (Ubuntu 9.3.0-10ubuntu2) 9.3.0
Code:
std::string MongoDB::insertDocument(std::string database,
std::string collection, bsoncxx::document::view_or_value document)
{
try
{
mongocxx::uri uri(_connection_string);
mongocxx::client conn(uri); // seg fault occurs here
mongocxx::database db = conn[database];
mongocxx::collection coll = db[collection];
auto inserted = coll.insert_one(document.view());
bsoncxx::oid oid = inserted->inserted_id().get_oid().value;
return oid.to_string();
}
catch (const mongocxx::exception & e)
{
std::cerr << "WARNING: Unable to connect to MongoDB" << std::endl;
return "UNKNOWN";
}
}
Variable values:
_connection_string = "mongodb://burns"
database = "hopping"
collection = "executions"
document =
{
"created_at" : "2020.09.29 10:48:51",
"hostname" : "XXXXX",
"interface" : "wlp3s0mon",
"schedule" : [ 1 ],
"slot_size" : 200,
"type" : "MOCK_NODE"
}
Log:
==213== Invalid read of size 8
==213== at 0x5695C0A: mongoc_counter_clients_active_add (mongoc-counters.defs:37)
==213== by 0x5695C0A: mongoc_counter_clients_active_inc (mongoc-counters.defs:37)
==213== by 0x5695C0A: _mongoc_client_new_from_uri (mongoc-client.c:1101)
==213== by 0x5318074: mongocxx::v_noabi::client::client(mongocxx::v_noabi::uri const&, mongocxx::v_noabi::options::client const&) (in /usr/local/lib/libmongocxx.so.3.5.0)
==213== by 0x4B691D0: MongoDB::insertDocument(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bsoncxx::v_noabi::view_or_value<bsoncxx::v_noabi::document::view, bsoncxx::v_noabi::document::value>) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x4B69714: MongoDB::insertJSONDocument(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, nlohmann::basic_json<std::map, std::vector, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bool, long, unsigned long, double, std::allocator, nlohmann::adl_serializer, std::vector<unsigned char, std::allocator<unsigned char> > >) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x4B61AD0: DataLogger::setExecutionParameters(nlohmann::basic_json<std::map, std::vector, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bool, long, unsigned long, double, std::allocator, nlohmann::adl_serializer, std::vector<unsigned char, std::allocator<unsigned char> > >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x1C232B: main (in /root/mock_node/build/mock_node)
==213== Address 0x38 is not stack'd, malloc'd or (recently) free'd
==213==
==213==
==213== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==213== Access not within mapped region at address 0x38
==213== at 0x5695C0A: mongoc_counter_clients_active_add (mongoc-counters.defs:37)
==213== by 0x5695C0A: mongoc_counter_clients_active_inc (mongoc-counters.defs:37)
==213== by 0x5695C0A: _mongoc_client_new_from_uri (mongoc-client.c:1101)
==213== by 0x5318074: mongocxx::v_noabi::client::client(mongocxx::v_noabi::uri const&, mongocxx::v_noabi::options::client const&) (in /usr/local/lib/libmongocxx.so.3.5.0)
==213== by 0x4B691D0: MongoDB::insertDocument(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bsoncxx::v_noabi::view_or_value<bsoncxx::v_noabi::document::view, bsoncxx::v_noabi::document::value>) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x4B69714: MongoDB::insertJSONDocument(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, nlohmann::basic_json<std::map, std::vector, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bool, long, unsigned long, double, std::allocator, nlohmann::adl_serializer, std::vector<unsigned char, std::allocator<unsigned char> > >) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x4B61AD0: DataLogger::setExecutionParameters(nlohmann::basic_json<std::map, std::vector, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, bool, long, unsigned long, double, std::allocator, nlohmann::adl_serializer, std::vector<unsigned char, std::allocator<unsigned char> > >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) (in /usr/local/lib/influx_logging/libinflux_logging.so)
==213== by 0x1C232B: main (in /root/mock_node/build/mock_node)
==213== If you believe this happened as a result of a stack
==213== overflow in your program's main thread (unlikely but
==213== possible), you can try to increase the size of the
==213== main thread stack using the --main-stacksize= flag.
==213== The main thread stack size used in this run was 8388608.
==213==
==213== HEAP SUMMARY:
==213== in use at exit: 123,339 bytes in 262 blocks
==213== total heap usage: 3,719 allocs, 3,457 frees, 367,254 bytes allocated
==213==
==213== LEAK SUMMARY:
==213== definitely lost: 400 bytes in 1 blocks
==213== indirectly lost: 6,752 bytes in 20 blocks
==213== possibly lost: 576 bytes in 2 blocks
==213== still reachable: 115,611 bytes in 239 blocks
==213== suppressed: 0 bytes in 0 blocks
==213== Rerun with --leak-check=full to see details of leaked memory
==213==
==213== For lists of detected and suppressed errors, rerun with: -s
==213== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Segmentation fault (core dumped)
Ps: mock_node is my executable and influxdb-logging is a library of mine.
Thank you very much,
I have no idea what could be causing this...
From Tutorial for mongocxx:
IMPORTANT: Before making any connections, you need to create one and only one instance of mongocxx::instance. This instance must exist for the entirety of your program.
So, you can add this as a static member of your MongoDB class:
header
class MongoDB {
//...
private:
static mongocxx::instance inst;
};
impl
mongocxx::instance MongoDB::inst{};
Here's an example where I connect to the the default mongodb server (mongodb://localhost:27017), use the database dbted and the collection movie, both of which previously created using the mongo cli.
I added a method to get a mongocxx::cursor to all documents in the collection.
#include <bsoncxx/builder/stream/document.hpp>
#include <bsoncxx/json.hpp>
#include <mongocxx/client.hpp>
#include <mongocxx/exception/exception.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <iostream>
class MongoDB {
public:
MongoDB() :
client{mongocxx::uri{"mongodb://localhost:27017"}},
db{client["dbted"]},
coll{db["movie"]}
{}
mongocxx::cursor all() { return coll.find({}); }
private
mongocxx::client client;
mongocxx::database db;
mongocxx::collection coll;
static mongocxx::instance inst;
};
mongocxx::instance MongoDB::inst{};
int main() {
try {
MongoDB db;
std::cout << "Connected successfully\n";
for(auto doc : db.all()) {
std::cout << bsoncxx::to_json(doc) << '\n';
}
} catch(const std::exception& ex) {
std::cerr << "Exception: " << ex.what() << std::endl;
return 1;
}
}
I already read similar posts on Stackoverflow but they do not solve my problem.
My problem
I get the following error message from Valgrind when I run the debug version of the executable with Valgrind.
==16631== Invalid read of size 8
==16631== at 0x217890: std::__detail::__variant::_Uninitialized<long long, true>::_Uninitialized<long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:222)
==16631== by 0x2178C9: std::__detail::__variant::_Variadic_union<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variadic_union<long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:342)
==16631== by 0x2178FD: std::__detail::__variant::_Variant_storage<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:399)
==16631== by 0x2156F0: std::__detail::__variant::_Copy_ctor_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:504)
==16631== by 0x215716: std::__detail::__variant::_Move_ctor_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:532)
==16631== by 0x21573C: std::__detail::__variant::_Copy_assign_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:592)
==16631== by 0x215762: std::__detail::__variant::_Move_assign_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:649)
==16631== by 0x215791: std::__detail::__variant::_Variant_base<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_base<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:701)
==16631== by 0x213F29: std::variant<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::variant<0ul, long long const&, long long, void>(std::in_place_index_t<0ul>, long long const&) (variant:1398)
==16631== by 0x213F6B: std::variant<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::variant<long long const&, void, void, long long, void>(long long const&) (variant:1369)
==16631== by 0x20B8ED: tgbot::Endpoints::deleteMessage(long long const&, int const&) const (Endpoints.cpp:1957)
==16631== by 0x2B17F6: ChatCleaner::run(std::shared_ptr<tgbot::Bot> const&) (ChatCleaner.cpp:40)
==16631== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==16631==
==16631==
==16631== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==16631== Access not within mapped region at address 0x0
==16631== at 0x217890: std::__detail::__variant::_Uninitialized<long long, true>::_Uninitialized<long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:222)
==16631== by 0x2178C9: std::__detail::__variant::_Variadic_union<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variadic_union<long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:342)
==16631== by 0x2178FD: std::__detail::__variant::_Variant_storage<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:399)
==16631== by 0x2156F0: std::__detail::__variant::_Copy_ctor_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:504)
==16631== by 0x215716: std::__detail::__variant::_Move_ctor_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:532)
==16631== by 0x21573C: std::__detail::__variant::_Copy_assign_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:592)
==16631== by 0x215762: std::__detail::__variant::_Move_assign_base<false, long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_storage<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:649)
==16631== by 0x215791: std::__detail::__variant::_Variant_base<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::_Variant_base<0ul, long long const&>(std::in_place_index_t<0ul>, long long const&) (variant:701)
==16631== by 0x213F29: std::variant<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::variant<0ul, long long const&, long long, void>(std::in_place_index_t<0ul>, long long const&) (variant:1398)
==16631== by 0x213F6B: std::variant<long long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::shared_ptr<tools::InputFile> >::variant<long long const&, void, void, long long, void>(long long const&) (variant:1369)
==16631== by 0x20B8ED: tgbot::Endpoints::deleteMessage(long long const&, int const&) const (Endpoints.cpp:1957)
==16631== by 0x2B17F6: ChatCleaner::run(std::shared_ptr<tgbot::Bot> const&) (ChatCleaner.cpp:40)
==16631== If you believe this happened as a result of a stack
==16631== overflow in your program's main thread (unlikely but
==16631== possible), you can try to increase the size of the
==16631== main thread stack using the --main-stacksize= flag.
==16631== The main thread stack size used in this run was 8388608.
==16631==
==16631== HEAP SUMMARY:
==16631== in use at exit: 317,149 bytes in 4,488 blocks
==16631== total heap usage: 1,171,900 allocs, 1,167,412 frees, 359,098,054 bytes allocated
==16631==
==16631== LEAK SUMMARY:
==16631== definitely lost: 0 bytes in 0 blocks
==16631== indirectly lost: 0 bytes in 0 blocks
==16631== possibly lost: 0 bytes in 0 blocks
==16631== still reachable: 317,045 bytes in 4,487 blocks
==16631== suppressed: 104 bytes in 1 blocks
==16631== Reachable blocks (those to which a pointer was found) are not shown.
==16631== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==16631==
==16631== For lists of detected and suppressed errors, rerun with: -s
==16631== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Speicherzugriffsfehler (Speicherabzug geschrieben)
The suitable source code
"m_msgs_to_delete" is a static vector in the class ChatCleaner.
32void ChatCleaner::run(const tgbot::Bot::ptr &bot) noexcept
33{
34 if(!m_msgs_to_delete.empty())
35 {
36 //Reverse to have the oldest message at the end.
37 std::reverse(m_msgs_to_delete.begin(), m_msgs_to_delete.end());
38
39 //Delete the message.
40 bot->get_endpnts()->deleteMessage(m_msgs_to_delete.at(m_msgs_to_delete.size() - 1)->chat->id, m_msgs_to_delete.at(m_msgs_to_delete.size() - 1)->message_id);
41 m_msgs_to_delete.pop_back();
42
43 //Reverse again.
44 std::reverse(m_msgs_to_delete.begin(), m_msgs_to_delete.end());
45
46 m_last_time = tools::Tools::get_time();
47 m_msgs_to_delete.shrink_to_fit();
48 }
49}
1953 bool Endpoints::deleteMessage(const long long &chat_id, const int &message_id) const noexcept
{
//HTTP arguments
std::vector<tools::HttpArg> http_args;
1957 http_args.push_back(tools::HttpArg("chat_id", chat_id));
http_args.push_back(tools::HttpArg("message_id", message_id));
tools::HttpClient http_client("https://api.telegram.org/bot" + m_token + "/deleteMessage", http_args);
std::string json = http_client.send_post_req_multipart().m_body;
1963 rapidjson::Document doc;
doc.Parse(json.c_str());
if(doc.IsObject())
if(doc.HasMember("result"))
if(doc["result"].IsBool())
1969 return doc["result"].GetBool();
else
tools::Tools::write_err_log(Messages::field_does_not_contain_bool("result"));
else
tools::Tools::write_err_log_tmp(Messages::field_non_existent("result"));
else
tools::Tools::write_err_log(Messages::server_resp_not_json_object);
1976
1977 return false;
1978 }
From what I see the error occurs in line 40 of the snippet above as that is an excerpt from the file ChatCleaner.cpp. This line accesses a vector which can totally be the error as users with similar problems on Stackoverflow also had problems with vector or array accessing. Unfortunately, I cannot see what I did wrong. This error error happens absolutely arbitrarily and I cannot reproduce it.
Additional notes that might help
The code is from a my chat bot for Telegram which runs 24/7.
The error can happen a few minutes after starting the software or after days or weeks.
The vector contains std::shared_ptr<> of sent messages which shall be deleted after a while.
I already checked whether the vector content may be broken which was not the case when the error occurred. The chat and message ID were totally fine. I highly assume that is just a memory accessing problem but I cannot figure out the soure of the problem.
Question
What is the cause of the problem?
I finally found the source of the problem with the help of the hints #cdhowie gave. The member variable "chat" of the Message object caused the problem since as you can see here
if(doc.HasMember("chat"))
{
if(doc["chat"].IsObject())
chat = std::make_shared<Chat>(tools::Tools::get_json_as_string(doc["chat"]));
else
tools::Tools::write_err_log(Messages::field_does_not_contain_json_obj("chat"));
}
this part of the Message constructor only creates a chat instance if the passed HTTP response body contains the proper field. Therefore, this member access m_msgs_to_delete.at(m_msgs_to_delete.size() - 1)->chat->id in line 40 of ChatCleaner.cpp called a null pointer as "chat" does not exist on the heap in this case.
PS: The object doc above comes from the library rapidjson. The definition is rapidjson::Document doc;. Its purpose is parsing JSON objects and making data accessible. The whole source code is from my Telegram chat bot.
I've been having a problem with allocating memory for one of my data structures. It always crashes out, but it's not always at the same place. My suspicion is that I'm trying to allocate it over the top of something that's already there, but I'm really not sure how to tell what's actually going on or how to fix it - I've tried to install valgrind, but that doesn't yet support Mac OS 10.10.
This is the code that calls the function.
stet::file f1;
f1.set_path("test/longfile1.txt"); // a file with almost 2 million lines
f1.read();
std::string all_text = f1.get_contents();
std::vector<chunk *> chunks = populate_chunks(all_text);
These are my data structures - the idea is that the text from file is split into fixed sized chunks, which are populated up to 75% capacity, but I can't seem to create all the chunks.
struct line {
std::string text;
};
struct chunk {
line *lines[MAX_CHUNK_SIZE];
};
And this is the cause of my nightmares - it crashes out on the line below all the comments.
std::vector<chunk *> populate_chunks(std::string &text) {
std::vector<std::string> all_lines;
boost::split(all_lines, text, boost::is_any_of("\n"));
size_t num_lines = all_lines.size();
std::vector<chunk *> chunks = std::vector<chunk *>( (num_lines / START_CHUNK_SIZE) * 2 );
size_t next_line_num;
for(size_t line_num = 0; line_num < num_lines; line_num = next_line_num) {
next_line_num = line_num + START_CHUNK_SIZE;
std::cout << line_num << std::endl;
chunk *c = new chunk;
chunks.push_back(c);
// This always falls over, but not always at the same point in the file.
// Never seems to be the first time. Observed range: 3072 - 59904
// Error always looks something like this:
// text(71184,0x7fff77699300) malloc: *** error for object 0x7ff389006208: incorrect checksum for freed object - object was probably modified after being freed.
// *** set a breakpoint in malloc_error_break to debug
for(size_t i = 0; i < next_line_num; ++i) {
line *l = new line;
l->text = all_lines[line_num+i];
c->lines[i] = l;
}
}
return chunks;
}
If anyone has any ideas, they'd be much appreciated - it should be noted that I'm pretty new to C++, so it's quite likely that I've missed something really stupid.
Update:
I've fiddled around with the code to change things based on the comments I've been getting:
Made chunks the function's return value, rather than a pointer
Stopped giving the all_lines vector a size on creation, allowed boost to sort that out
I also got a fedora VM up and running in order to put it through valgrind and I'm really very confused by the output.
Noted the values of MAX_CHUNK_SIZE and START_CHUNK_SIZE below.
Macro values:
#define MAX_CHUNK_SIZE 1024
#define START_CHUNK_SIZE MAX_CHUNK_SIZE * 0.75
Valgrind output after the above changes:
==24468== Memcheck, a memory error detector
==24468== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==24468== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==24468== Command: bin/text
==24468==
==24468== Invalid write of size 8
==24468== at 0x402907: populate_chunks(std::string&) (text_storage.cc:125)
==24468== by 0x402ADF: main (text_storage.cc:173)
==24468== Address 0x216b5640 is 0 bytes after a block of size 8,192 alloc'd
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x402888: populate_chunks(std::string&) (text_storage.cc:113)
==24468== by 0x402ADF: main (text_storage.cc:173)
==24468==
==24468==
==24468== Process terminating with default action of signal 11 (SIGSEGV)
==24468== Access not within mapped region at address 0x37D77000
==24468== at 0x402907: populate_chunks(std::string&) (text_storage.cc:125)
==24468== by 0x402ADF: main (text_storage.cc:173)
==24468== If you believe this happened as a result of a stack
==24468== overflow in your program's main thread (unlikely but
==24468== possible), you can try to increase the size of the
==24468== main thread stack using the --main-stacksize= flag.
==24468== The main thread stack size used in this run was 8388608.
==24468==
==24468== HEAP SUMMARY:
==24468== in use at exit: 371,641,698 bytes in 6,241,143 blocks
==24468== total heap usage: 6,241,190 allocs, 47 frees, 656,880,685 bytes allocated
==24468==
==24468== 16 bytes in 2 blocks are possibly lost in loss record 1 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x4028BC: populate_chunks(std::string&) (text_storage.cc:123)
==24468== by 0x402ADF: main (text_storage.cc:173)
==24468==
==24468== 43 bytes in 1 blocks are possibly lost in loss record 2 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x5340048: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x5341900: char* std::string::_S_construct<char const*>(char const*, char const*, std::allocator<char> const&, std::forward_iterator_tag) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x5341D37: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x4029F7: main (text_storage.cc:138)
==24468==
==24468== 35,727,800 (33,173,592 direct, 2,554,208 indirect) bytes in 4,146,699 blocks are definitely lost in loss record 8 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x4028BC: populate_chunks(std::string&) (text_storage.cc:123)
==24468== by 0x402ADF: main (text_storage.cc:173)
==24468==
==24468== 93,350,023 bytes in 1 blocks are possibly lost in loss record 9 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x5340048: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x5340235: std::string::_M_mutate(unsigned long, unsigned long, unsigned long) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x53403C5: std::string::_M_leak_hard() (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x5340412: std::string::begin() (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x407728: boost::range_iterator<std::string>::type boost::range_detail::range_begin<std::string>(std::string&) (begin.hpp:49)
==24468== by 0x40705D: boost::range_iterator<std::string>::type boost::range_adl_barrier::begin<std::string>(std::string&) (begin.hpp:108)
==24468== by 0x4066FC: __gnu_cxx::__normal_iterator<char*, std::string> boost::iterator_range_detail::iterator_range_impl<__gnu_cxx::__normal_iterator<char*, std::string> >::adl_begin<std::string>(std::string&) (iterator_range_core.hpp:58)
==24468== by 0x40601A: boost::iterator_range<__gnu_cxx::__normal_iterator<char*, std::string> >::iterator_range<std::string>(std::string&, boost::iterator_range_detail::range_tag) (iterator_range_core.hpp:207)
==24468== by 0x40561F: boost::iterator_range<boost::range_iterator<std::string>::type> boost::make_iterator_range<std::string>(std::string&) (iterator_range_core.hpp:559)
==24468== by 0x404BC3: boost::iterator_range<boost::range_iterator<std::string>::type> boost::range_detail::make_range<std::string>(std::string&, long) (as_literal.hpp:93)
==24468== by 0x4040E5: boost::iterator_range<boost::range_iterator<std::string>::type> boost::as_literal<std::string>(std::string&) (as_literal.hpp:102)
==24468==
==24468== 93,351,904 bytes in 1 blocks are possibly lost in loss record 10 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x5340048: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x5341710: char* std::string::_S_construct<char*>(char*, char*, std::allocator<char> const&, std::forward_iterator_tag) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x531F9A7: std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >::str() const (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x402523: stet::file::read() (file.cc:50)
==24468== by 0x402A2E: main (text_storage.cc:139)
==24468==
==24468== 129,441,960 bytes in 1,520,226 blocks are possibly lost in loss record 11 of 11
==24468== at 0x4C27965: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==24468== by 0x5340048: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.19)
==24468== by 0x40845E: char* std::string::_S_construct<__gnu_cxx::__normal_iterator<char*, std::string> >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, std::allocator<char> const&, std::forward_iterator_tag) (basic_string.tcc:138)
==24468== by 0x4082E8: char* std::string::_S_construct_aux<__gnu_cxx::__normal_iterator<char*, std::string> >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, std::allocator<char> const&, std::__false_type) (basic_string.h:1725)
==24468== by 0x408177: char* std::string::_S_construct<__gnu_cxx::__normal_iterator<char*, std::string> >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, std::allocator<char> const&) (basic_string.h:1746)
==24468== by 0x407FDA: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string<__gnu_cxx::__normal_iterator<char*, std::string> >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, std::allocator<char> const&) (basic_string.tcc:229)
==24468== by 0x407D6A: std::string boost::copy_range<std::string, boost::iterator_range<__gnu_cxx::__normal_iterator<char*, std::string> > >(boost::iterator_range<__gnu_cxx::__normal_iterator<char*, std::string> > const&) (iterator_range_core.hpp:643)
==24468== by 0x407AEA: boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >::operator()(boost::iterator_range<__gnu_cxx::__normal_iterator<char*, std::string> > const&) const (util.hpp:97)
==24468== by 0x407395: boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default>::dereference() const (transform_iterator.hpp:121)
==24468== by 0x406B72: boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default>::reference boost::iterator_core_access::dereference<boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default> >(boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default> const&) (iterator_facade.hpp:514)
==24468== by 0x40633D: boost::iterator_facade<boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default>, std::string, boost::forward_traversal_tag, std::string, long>::operator*() const (iterator_facade.hpp:639)
==24468== by 0x405895: void std::vector<std::string, std::allocator<std::string> >::_M_range_initialize<boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default> >(boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default>, boost::transform_iterator<boost::algorithm::detail::copy_iterator_rangeF<std::string, __gnu_cxx::__normal_iterator<char*, std::string> >, boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::string> >, boost::use_default, boost::use_default>, std::input_iterator_tag) (stl_vector.h:1188)
==24468==
==24468== LEAK SUMMARY:
==24468== definitely lost: 33,173,592 bytes in 4,146,699 blocks
==24468== indirectly lost: 2,554,208 bytes in 319,276 blocks
==24468== possibly lost: 316,143,946 bytes in 1,520,231 blocks
==24468== still reachable: 19,769,952 bytes in 254,937 blocks
==24468== suppressed: 0 bytes in 0 blocks
==24468== Reachable blocks (those to which a pointer was found) are not shown.
==24468== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==24468==
==24468== For counts of detected and suppressed errors, rerun with: -v
==24468== ERROR SUMMARY: 4146708 errors from 7 contexts (suppressed: 2 from 2)
The size of the lines array in a chunk is MAX_CHUNK_SIZE, but you are accessing it far beyond that on any iteration except the first.
Your loop is for(size_t i = 0; i < next_line_num; ++i), guess what next_line_num is on your second (and beyond) iteration?
You would probably have totally avoided this problem if you had thought of another problem, which you overlooked. You only partially fill the chunks (by 75%), which makes sense. But on the last iteration you are likely to have even less lines than those needed to fill 75% of a chunk. Therefore there should be, somewhere, a test to handle this boundary. A comparison, somewhere in that loop, with num_lines. Thinking about where to put it could (but not necessarily would) have alerted you that the iteration index is not doing what you expect.
Try for(size_t i = 0; i < START_CHUNK_SIZE && line_num+i < num_lines; ++i).
For reference, this is what the final code looks like:
std::vector<chunk *> populate_chunks(std::string &text) {
std::vector<std::string> all_lines;
boost::split(all_lines, text, boost::is_any_of("\n"));
size_t num_lines = all_lines.size();
std::vector<chunk *> chunks = std::vector<chunk *>( (num_lines / START_CHUNK_SIZE) * 2 );
for(size_t next_line_num, line_num = 0; line_num < num_lines; line_num = next_line_num) {
next_line_num = line_num + START_CHUNK_SIZE;
chunk *c = new chunk;
chunks.push_back(c);
for(size_t i = 0; i < std::min(static_cast<unsigned int>(START_CHUNK_SIZE), static_cast<unsigned int>(num_lines - line_num) ); ++i) {
line *l = new line;
l->text = all_lines[line_num+i];
c->lines[i] = l;
}
}
return chunks;
}
This is a related post to this one as it deals with the same program, but i now implemented it iterative and not recursive anymore, but I still get SIGSEGV (but later) while running the program. I did some other changes to my program to narrow it down, and I figured that changing a vector of objects, to a vector of ptr to the objects on the heap does give me some extra rounds (about 200), but still crashes. I suggest that somehow my memory to save variables within the program gets exhausted, but as I dump the stacksize of the program:
rlimit rlim;
getrlimit(RLIMIT_STACK,&rlim);
std::cout << "rlim_cur ist:" << rlim.rlim_cur << std::endl;
std::cout << "rlim_max ist:" << rlim.rlim_max << std::endl;
the output is:
rlim_cur ist:8388608
rlim_max ist:18446744073709551615
and this seems to be pretty big and not used up, are there any other relevant limits to dump
to narrow my problem down further and hopefully solve it?
Here the dump of my debugger:
Program received signal SIGSEGV, Segmentation fault.
0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
98 return left_over_capacity;
(gdb) backtrace
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
#1 0x000000000040b9ab in Town::compare_by_capacity (eins=0x0, zwei=0x0) at ./solver/Darstellung.cpp:135
#2 0x00000000004124c7 in std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__a=..., __b=..., __c=...,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:108
#3 0x0000000000411250 in std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=...,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2260
#4 0x000000000040f111 in std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, long, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __depth_limit=21,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2302
#5 0x000000000040de63 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:5250
#6 0x000000000040ce5a in Solution_Stack::get_towns_by_capacity (this=0x7fffffffe010) at ./solver/Darstellung.cpp:331
#7 0x000000000040a6cf in solver::treat_towns_with_zero_capacity (ptr=0x7fffffffe010) at ./solver/Solver.cpp:184
#8 0x0000000000409ff2 in solver::solve_problem (ptr=0x7fffffffe010) at ./solver/Solver.cpp:94
#9 0x000000000041475f in main (argc=3, argv=0x7fffffffe208) at ./main/Main.cpp:50
The new dump after adding a check-function to trace down zero values:
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x40) at ./solver/Darstellung.cpp:98
#1 0x000000000040b9e9 in Town::compare_by_index (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:139
#2 0x000000000040bad1 in Town::compare_by_index_inv (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:153
#3 0x00000000004127ea in std::__unguarded_partition<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, Town*, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __pivot=#0x631ef0, __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:2229
#4 0x0000000000411444 in std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2261
#5 0x000000000040f2c5 in std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, long, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __depth_limit=7, __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:2302
#6 0x000000000040e017 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=...,
__comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:5250
#7 0x000000000040d1e6 in Solution_Stack::get_partners_of_by_index_inv (this=0x7fffffffe010, id=523) at ./solver/Darstellung.cpp:371
#8 0x000000000040a4d7 in solver::treat_towns_considering_their_index (ptr=0x7fffffffe010) at ./solver/Solver.cpp:165
#9 0x000000000040a016 in solver::solve_problem (ptr=0x7fffffffe010) at ./solver/Solver.cpp:100
#10 0x0000000000414913 in main (argc=3, argv=0x7fffffffe208) at ./main/Main.cpp:50
Valgrind gave me this as a dump, just at the place where the problem used to occure anyways. I is quite confusing to me, due to its size:
==16150== Invalid read of size 4
==16150== at 0x40B2A0: Town::get_cur_capacity() const (Darstellung.cpp:98)
==16150== by 0x40B9AA: Town::compare_by_capacity(Town const*, Town const*) (Darstellung.cpp:135)
==16150== by 0x4124C6: void std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:108)
==16150== by 0x41124F: __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > > std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:2260)
==16150== by 0x40F110: void std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)) (stl_algo.h:2302)
==16150== by 0x40DE62: void std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:5250)
==16150== by 0x40CE59: Solution_Stack::get_towns_by_capacity() (Darstellung.cpp:331)
==16150== by 0x40A6CE: solver::treat_towns_with_zero_capacity(Solution_Stack*) (Solver.cpp:184)
==16150== by 0x409FF1: solver::solve_problem(Solution_Stack*) (Solver.cpp:94)
==16150== by 0x41475E: main (Main.cpp:50)
==16150== Address 0x8 is not stack'd, malloc'd or (recently) free'd
==16150==
==16150==
==16150== Process terminating with default action of signal 11 (SIGSEGV)
==16150== Access not within mapped region at address 0x8
==16150== at 0x40B2A0: Town::get_cur_capacity() const (Darstellung.cpp:98)
==16150== by 0x40B9AA: Town::compare_by_capacity(Town const*, Town const*) (Darstellung.cpp:135)
==16150== by 0x4124C6: void std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:108)
==16150== by 0x41124F: __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > > std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:2260)
==16150== by 0x40F110: void std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)) (stl_algo.h:2302)
==16150== by 0x40DE62: void std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:5250)
==16150== by 0x40CE59: Solution_Stack::get_towns_by_capacity() (Darstellung.cpp:331)
==16150== by 0x40A6CE: solver::treat_towns_with_zero_capacity(Solution_Stack*) (Solver.cpp:184)
==16150== by 0x409FF1: solver::solve_problem(Solution_Stack*) (Solver.cpp:94)
==16150== by 0x41475E: main (Main.cpp:50)
==16150== If you believe this happened as a result of a stack
==16150== overflow in your program's main thread (unlikely but
==16150== possible), you can try to increase the size of the
==16150== main thread stack using the --main-stacksize= flag.
==16150== The main thread stack size used in this run was 8388608.
==16150==
==16150== HEAP SUMMARY:
==16150== in use at exit: 771,174 bytes in 19,239 blocks
==16150== total heap usage: 9,821,251 allocs, 9,802,012 frees, 384,861,557 bytes allocated
==16150==
==16150== 50,678 bytes in 1,491 blocks are possibly lost in loss record 28 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x4ECBE6C: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x4ECC08D: std::string::_M_mutate(unsigned long, unsigned long, unsigned long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x4ECC730: std::string::erase(unsigned long, unsigned long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x407FB6: utility::split_helper(std::string, std::string) (Tools.cpp:28)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40539C: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:27)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 62,606 (11,928 direct, 50,678 indirect) bytes in 1,491 blocks are definitely lost in loss record 30 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x407F68: utility::split_helper(std::string, std::string) (Tools.cpp:24)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40539C: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:27)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 94,406 (18,440 direct, 75,966 indirect) bytes in 2,305 blocks are definitely lost in loss record 32 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x407F68: utility::split_helper(std::string, std::string) (Tools.cpp:24)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40573F: parser::get_finished_cities(std::vector<std::string, std::allocator<std::string> >, std::vector<City*, std::allocator<City*> >) (Parser.cpp:42)
==16150== by 0x40511A: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 178,720 (131,208 direct, 47,512 indirect) bytes in 1,491 blocks are definitely lost in loss record 35 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x40541B: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:28)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== LEAK SUMMARY:
==16150== definitely lost: 161,576 bytes in 5,287 blocks
==16150== indirectly lost: 174,156 bytes in 5,287 blocks
==16150== possibly lost: 50,678 bytes in 1,491 blocks
==16150== still reachable: 384,764 bytes in 7,174 blocks
==16150== suppressed: 0 bytes in 0 blocks
==16150== Reachable blocks (those to which a pointer was found) are not shown.
==16150== To see them, rerun with: --leak-check=full --show-reachable=yes
==16150==
==16150== For counts of detected and suppressed errors, rerun with: -v
==16150== Use --track-origins=yes to see where uninitialised values come from
==16150== ERROR SUMMARY: 7 errors from 7 contexts (suppressed: 4 from 4)
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
It looks like you're invoking get_cur_capacity on a NULL pointer. You're getting here from a comparator:
#1 0x000000000040b9ab in Town::compare_by_capacity (eins=0x0, zwei=0x0) at ./solver/Darstellung.cpp:135
which is comparing NULL to NULL. You further get here from a sort:
#5 0x000000000040de63 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:5250
This is sorting std::vector<Town*>, and is called from:
#6 0x000000000040ce5a in Solution_Stack::get_towns_by_capacity (this=0x7fffffffe010) at ./solver/Darstellung.cpp:331
Most likely the vector you're sorting contains NULL pointers, and your compare_by_capacity function is not prepared to handle this eventuality. Either make sure the vector has no NULLs, or have compare_by_capacity explicitly check for NULL and do something sensible (eg, sort it before anything other than another NULL).
#1 0x000000000040b9e9 in Town::compare_by_index (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:139
This 0x40 looks like you have either uninitialized memory or corrupted memory. How are you resizing this vector?
It's really quite difficult to try to diagnose this without actually seeing any of your code.
If your code is compiled with debugging symbols and without optimization, then we can probably believe the Town::get_cur_capacity (this=0x0) line which means you got a null pointer in your vector somewhere. The code that put it in may have run at a totally different point in time.
If nulls are actually intended to be allowed in your vector then your sort predicate compare_by_capacity needs to be prepared to handle that eventuality.
In this case you may need to review the code that populates your vector, and valgrind may help you track down if there are memory problems in your code.