std::string memory leak

Question

I've got this class AppController and the function connectPlayer:

/* AppController.h */
    class AppController
    {
          // Some other declarations ...
      private:
            static const string TAG;
    };

/* AppController.cpp */

#include "AppController.h"
const string AppController::TAG = "AppController";

AppController::AppController() {
    /* some code here...*/
}

void AppController::connectPlayer() {
    std::string port;
    std::string host;
    port = CM->getMenu()->getData("PORT");
    host = CM->getMenu()->getData("HOST");
    this->setState("Connecting...");
    Logger::info(TAG, "Port: " + port);
    Logger::info(TAG, "Host: " + host);
}

And when I execute the program, I get this from valgrind:

==7848== 25 bytes in 1 blocks are definitely lost in loss record 160 of 671
==7848==    at 0x402842F: operator new(unsigned int) (vg_replace_malloc.c:255)
==7848==    by 0x4210A83: std::string::_Rep::_S_create(unsigned int, unsigned int, std::allocator<char> const&) (in /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16)
==7848==    by 0x4212CF7: char* std::string::_S_construct<char const*>(char const*, char const*, std::allocator<char> const&, std::forward_iterator_tag) (in /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16)
==7848==    by 0x4212E65: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) (in /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16)
==7848==    by 0x8080501: AppController::connectPlayer() (in /home/maine/Escritorio/taller7542/UltimaVersion/src/main)

Any ideas? Thank you in advance!

@PiotrNycz, it's just the name of the class. I use it to write in a Logger the important events that happen during the execution of the program. — Maria Ines Parnisari, Oct 21 '12 at 20:25
Having _non-POD_ objects of static duration (like your `AppController::TAG` which is a `std::string`) may not be good thing. You may want to try use a POD like a simple `const char []` instead. See also [this section from Google's C++ style guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Static_and_Global_Variables). — Mr.C64, Oct 22 '12 at 08:57

PiotrNycz · Accepted Answer · 2012-10-21T20:36:31.793

7

You have std::string objects in global scope: AppController::TAG.

When application finished in not very normal way you've got these kind of valgrind errors for global objects. Probably nothing to worry.

If you (cannot/don't want to) change your program - read this doc: http://valgrind.org/docs/manual/manual-core.html#manual-core.suppress to get rid of this very error.

edited Oct 21 '12 at 20:36

answered Oct 21 '12 at 20:29

PiotrNycz

23,099
7
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score 1 · Answer 2 · edited May 23 '17 at 12:25

1

Sometimes, valgrind gives false positives. This means that even if valgrind says you lose memory, actually you don't.

The only thing to worry about is when you call the exit() function, as explained in this question.

If you do not want to see these warnings any more, you can create a suppressions file giving valgrind some information on which errors to ignore.

edited May 23 '17 at 12:25

Community

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answered Oct 21 '12 at 20:28

alestanis

21,519
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score 1 · Answer 3 · answered Dec 12 '14 at 09:48

1

I had seen this issue once when I had a string in a class in global scope. Valgrind kept complaining that I was leaking memory. I just "deleted" the object at exit and the error was gone.

answered Dec 12 '14 at 09:48

Mayukh

117
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std::string memory leak

3 Answers3

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