Valgrind C++ memory leak in empty file

Question

I have a problem with "extra" memory leaks in valgrind. For example, I created a test program, called temp.cpp:

int main() { return 0; }

In the terminal, I run:

>> g++ -o temp.out temp.cpp
>> valgrind --tool=memcheck --leak-check=full --show-leak-kinds=all ./temp.out

This results in several memory leaks. How could this be?

==4438== LEAK SUMMARY:
==4438==    definitely lost: 4,120 bytes in 2 blocks
==4438==    indirectly lost: 2,288 bytes in 6 blocks
==4438==      possibly lost: 8,336 bytes in 99 blocks
==4438==    still reachable: 6,440 bytes in 13 blocks  
==4438==         suppressed: 5,020 bytes in 73 blocks

I have tried running other .cpp files and I get the exact same leak summary. About a month ago when I tried, nothing was wrong. I might have upgraded Xcode or something, if that could be the issue (?). These are my settings for g++:

Configured with:

--prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/usr/include/c++/4.2.1

Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) Target: x86_64-apple-darwin15.0.0 Thread model: posix

Answer 1

It seems valgrind have issues on MacOSX. While these issues are not fixed, a possible temporary solution would be the use of a suppression file. For further details, please check this other answer

Answer 2

I tried to reproduce this but I couldn't on my machine. It seems that there is no leak on the newest valgrind. Try brew upgrade valgrind

C02QH2D7G8WM:simple userone$ valgrind --tool=memcheck --leak-check=full --show-leak-kinds=all ./temp.out
==1917== Memcheck, a memory error detector
==1917== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==1917== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==1917== Command: ./temp.out
==1917== 
==1917== 
==1917== HEAP SUMMARY:
==1917==     in use at exit: 22,177 bytes in 189 blocks
==1917==   total heap usage: 255 allocs, 66 frees, 27,953 bytes allocated
==1917== 
==1917== 2,064 bytes in 1 blocks are possibly lost in loss record 57 of 62
==1917==    at 0x10000817C: malloc_zone_malloc (in /usr/local/Cellar/valgrind/3.11.0/lib/valgrind/vgpreload_memcheck-amd64-darwin.so)
==1917==    by 0x1005E0EFD: _objc_copyClassNamesForImage (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D4182: protocols() (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D4093: readClass(objc_class*, bool, bool) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D1C13: gc_init (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D924E: objc_initializeClassPair_internal(objc_class*, char const*, objc_class*, objc_class*) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005E6132: layout_string_create (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D483C: realizeClass(objc_class*) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D4300: copySwiftV1MangledName(char const*, bool) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D42E9: copySwiftV1MangledName(char const*, bool) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D42E9: copySwiftV1MangledName(char const*, bool) (in /usr/lib/libobjc.A.dylib)
==1917==    by 0x1005D42E9: copySwiftV1MangledName(char const*, bool) (in /usr/lib/libobjc.A.dylib)
==1917== 
==1917== LEAK SUMMARY:
==1917==    definitely lost: 0 bytes in 0 blocks
==1917==    indirectly lost: 0 bytes in 0 blocks
==1917==      possibly lost: 2,064 bytes in 1 blocks
==1917==    still reachable: 0 bytes in 0 blocks
==1917==         suppressed: 20,113 bytes in 188 blocks
==1917== 
==1917== For counts of detected and suppressed errors, rerun with: -v
==1917== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 17 from 17)