基本的なQtアプリケーションでのValgrind

Question

Valgrindを実行すると単純なMakefileからコンパイルされた基本的なQt4アプリケーションに何が起こるかを見たいと思っていました。これらのリークの原因は何ですか？私は私の最後に動的に割り当てられたオブジェクトを削除しています。また、プログラムを終了するときには、右上隅の閉じる（X）をクリックするだけです。 GUIのlibsはちょうどではありません "無料（）" malloc（） 'dのいずれかのメモリのいずれかの？ qmakeのコマンドから減少

Makefileは次のとおりです。

####### Compiler, tools and options 

CXX   = g++ 
CXXFLAGS  = -pipe -O2 -Wall -W 
LIBS_INCLUDE = ${HOME} 
INCPATH  = -I$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/mkspecs/default \ 
       -I. \ 
       -I$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/include/QtCore \ 
       -I$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/include/QtGui \ 
       -I$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/include 
LINK   = g++ 
LFLAGS  = -Wl,-O1 -Wl,-rpath,$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/lib 
LIBS   = $(SUBLIBS) -L$(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/lib -lQtGui -lQtCore -lpthread 
QMAKE   = $(LIBS_INCLUDE)/QtSDK/Desktop/Qt/473/gcc/bin/qmake 
OBJECTS_DIR = ./ 
SOURCES  = main.cpp 
OBJECTS  = main.o 
QMAKE_TARGET = Main 
TARGET  = Main 

####### Build rules 
first: all 

all: $(TARGET) 

$(TARGET): $(OBJECTS) 
     $(LINK) $(LFLAGS) -o $(TARGET) $(OBJECTS) $(OBJCOMP) $(LIBS) 

####### Compile 

main.o: main.cpp 
     $(CXX) -c $(CXXFLAGS) $(INCPATH) -o main.o main.cpp 

唯一のソースコードは次のとおりです。

int main(int argc, char *argv[]) 
{ 
    QApplication app(argc, argv); 
    QWidget window; 
    window.resize(320,240); 
    window.setWindowTitle( 
     QApplication::translate("toplevel", "Top-level Widget")); 
    window.show(); 

    QPushButton *button = new QPushButton(
     QApplication::translate("childwidget", "Press me"), &window); 
    button->move(100, 100); 
    button->show(); 
    delete button; 
    return app.exec(); 
} 

valgrindのを介して実行すると、私は、次の（中東で削除大部分）を取得：

==3836== Memcheck, a memory error detector 
==3836== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al. 
==3836== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info 
==3836== Command: ./Main 
==3836== 
Xlib: extension "RANDR" missing on display ":0.0". 
==3836== 
==3836== HEAP SUMMARY: 
==3836==  in use at exit: 924,383 bytes in 8,679 blocks 
==3836== total heap usage: 37,234 allocs, 28,555 frees, 4,314,180 bytes allocated 
==3836== 
==3836== 1 bytes in 1 blocks are possibly lost in loss record 1 of 4,534 
==3836== at 0x400677E: malloc (vg_replace_malloc.c:195) 
==3836== by 0xA1DFA4: g_malloc (in /lib/libglib-2.0.so.0.2600.0) 
==3836== by 0xA37F29: g_strdup (in /lib/libglib-2.0.so.0.2600.0) 
==3836== by 0xB2A6FA: g_param_spec_string (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0x41F36473: ??? (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== by 0xB3D237: g_type_class_ref (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB20B38: g_object_newv (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB212EF: g_object_new (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0x41F34857: gtk_settings_get_for_screen (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== by 0x41ED0CB6: ??? (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== by 0xB377C7: g_cclosure_marshal_VOID__OBJECT (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB1ABE2: g_closure_invoke (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== 
... 
==3836== 
==3836== 23,048 bytes in 1 blocks are possibly lost in loss record 4,531 of 4,534 
==3836== at 0x400677E: malloc (vg_replace_malloc.c:195) 
==3836== by 0x16F42D: ??? (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x17400B: ft_mem_qalloc (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x174063: ft_mem_alloc (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x174508: ft_mem_qrealloc (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x17457F: ft_mem_realloc (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x1A2E52: ??? (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x1A709B: ??? (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x180338: ??? (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x175B5D: ??? (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x1780B0: FT_Open_Face (in /usr/lib/libfreetype.so.6.6.0) 
==3836== by 0x1791FF: FT_New_Face (in /usr/lib/libfreetype.so.6.6.0) 
==3836== 
==3836== 53,244 bytes in 29 blocks are possibly lost in loss record 4,534 of 4,534 
==3836== at 0x400677E: malloc (vg_replace_malloc.c:195) 
==3836== by 0xA1DFA4: g_malloc (in /lib/libglib-2.0.so.0.2600.0) 
==3836== by 0xA36050: g_slice_alloc (in /lib/libglib-2.0.so.0.2600.0) 
==3836== by 0xA36315: g_slice_alloc0 (in /lib/libglib-2.0.so.0.2600.0) 
==3836== by 0xB40077: g_type_create_instance (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB1CE35: ??? (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB205C6: g_object_newv (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0xB212EF: g_object_new (in /lib/libgobject-2.0.so.0.2600.0) 
==3836== by 0x54B8FA3: ??? (in /usr/lib/gtk-2.0/2.10.0/engines/libclearlooks.so) 
==3836== by 0x41F0CDDD: ??? (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== by 0x41F11C24: gtk_rc_get_style (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== by 0x4200A81F: ??? (in /usr/lib/libgtk-x11-2.0.so.0.2200.0) 
==3836== 
==3836== LEAK SUMMARY: 
==3836== definitely lost: 1,912 bytes in 7 blocks 
==3836== indirectly lost: 5,060 bytes in 250 blocks 
==3836==  possibly lost: 491,358 bytes in 2,893 blocks 
==3836== still reachable: 426,053 bytes in 5,529 blocks 
==3836==   suppressed: 0 bytes in 0 blocks 
==3836== Reachable blocks (those to which a pointer was found) are not shown. 
==3836== To see them, rerun with: --leak-check=full --show-reachable=yes 
==3836== 
==3836== For counts of detected and suppressed errors, rerun with: -v 
==3836== ERROR SUMMARY: 1336 errors from 1336 contexts (suppressed: 114 from 11) 

Answer 1

私は短いアプリケーションをコンパイルしました。（Visual Studioのcrt memoryleak検出器を使用して）はメモリリークを検出できませんでした。 valgrindが報告するものは、コードに直接関係しないものです。

ただし、アプリケーションが実際に実行される前にQPushButtonを削除しています。通常、QWindowsの所有権は親ウィンドウに移されますので、自分でオブジェクトをクリーンアップする必要はありません。親ウィンドウがそれを処理します（そうでない場合は、ドキュメントに記載されています）。

コードを修正するには、削除を削除してください。