C++ Program Always Crashes While doing a std::string assign

Question

I have been trying to debug a crash in my application that crashes (i.e. asserts a * glibc detected * free(): invalid pointer: 0x000000000070f0c0 ***) while I\

Answer 1

Can you repeat the crash with a basic two line program?

#include <string>

int main()
{
    std::string abc;
    abc = "testString";
}

If that crashes, please post your exact compile / link options?

If not, start paring down your code. Remove things lines a handful at a time until the bug goes away. Once you have some other change you can add to cause the crash and remove to make it go away, that should help you locate the problem.

Answer 2

This is an initial guess using all information I can extract from your back trace.

You are most likely mixing and matching gcc version, linker and libstdc++ that results an unusual behaviour on the host machine:

1. libc is the system's: /lib64/libc.so.6
2. libstdc++ is in a "ThirdParty" directory - this is suspicions, as it tells me it might be compiled elsewhere with a different target - /home/bbazso/ThirdParty/sources/gcc-4.2.4/x86_64-pc-linux-gnu/libstdc++-v3/
3. Yet another libstdc++ in /opt: /opt/trx-HEAD/gcc/4.2.4/lib/gcc/x86_64-pc-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/basic_string.h:491

In addition, GCC may mix the system's ld instead of itself which may cause further weird memory maps usage.

Answer 3

Happened to me because of using malloc for a class which had std::strings as data members. Tricky.

Answer 4

As you said it's a weird behavior.

To be honnest with i think you are wasting time looking into a possible bug with std::strings. Strings are perfectly safe as long as you are using them well.

Anyway, with the informations you are giving : First, are you using threads ? It's might be a thread problem. Second, you check your program using valgrind. Have you no warnings at all ?

Note : The most critical valgrind's warnings are invalid read and invalid write.

PS : As said in commentary, you should probably use g++ to compile C++ code ;)