A memory leak happens when std::ios::sync_with_stdio(false); valgrind: ... ==13644== ==13644== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 17 from 1) ==13644== malloc/free: in use at exit: 122,880 bytes in 6 blocks. ==13644== malloc/free: 6 allocs, 0 frees, 122,880 bytes allocated. ==13644== For counts of detected errors, rerun with: -v ==13644== searching for pointers to 6 not-freed blocks. ==13644== checked 96,388 bytes. ==13644== ==13644== 24,576 bytes in 3 blocks are still reachable in loss record 1 of 2 ==13644== at 0x401BCC9: operator new[](unsigned) (vg_replace_malloc.c:197) ==13644== by 0x4090D7B: std::basic_filebuf<char, std::char_traits<char> >::_M_allocate_internal_buffer() (in /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x4098805: (within /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x40862D6: std::ios_base::sync_with_stdio(bool) (in /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x8048712: main (in ...) ==13644== ==13644== ==13644== 98,304 bytes in 3 blocks are still reachable in loss record 2 of 2 ==13644== at 0x401BCC9: operator new[](unsigned) (vg_replace_malloc.c:197) ==13644== by 0x4090D2E: std::basic_filebuf<wchar_t, std::char_traits<wchar_t> >::_M_allocate_internal_buffer() (in /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x40981F5: (within /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x40863B4: std::ios_base::sync_with_stdio(bool) (in /usr/lib/libstdc++.so.6.0.8) ==13644== by 0x8048712: main (in ...) ==13644== ==13644== LEAK SUMMARY: ==13644== definitely lost: 0 bytes in 0 blocks. ==13644== possibly lost: 0 bytes in 0 blocks. ==13644== still reachable: 122,880 bytes in 6 blocks. ==13644== suppressed: 0 bytes in 0 blocks.
Environment: System: Linux penelope 2.6.15-1-k7 #2 Mon Mar 6 15:42:39 UTC 2006 i686 GNU/Linux Architecture: i686 host: i486-pc-linux-gnu build: i486-pc-linux-gnu target: i486-pc-linux-gnu configured with: ../src/configure -v --enable-languages=c,c++,java,fortran,objc,obj-c++,ada,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.1-1.4.2.0/jre --enable-mpfr --with-tune=i686 --enable-checking=release i486-linux-gnu How-To-Repeat: // run with valgrind --leak-check=full --show-reachable=yes #include <iostream> int main(void) { std::ios::sync_with_stdio(false); std::cout << "testing" << std::endl; return 0; } ------- Comment #1 from mirko dot maischberger at gmail dot com 2006-06-07 14:40 ------- Fix: std::ios::sync_with_stdio(true); -- Summary: valgrind reports memleak when std::ios:sync_with_stdio(false) Product: gcc Version: 4.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: mirko dot maischberger at gmail dot com GCC build triplet: i486-pc-linux-gnu GCC host triplet: i486-pc-linux-gnu GCC target triplet: i486-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27931