बेसिक क्यूटी एप्लीकेशन पर वालग्रिंड: रिपोर्ट्स मासिव लीक्स

Question

इसलिए मैं देखना चाहता था कि वैलग्रींड के माध्यम से चलने पर एक साधारण मेकफ़ाइल से संकलित मूल Qt4 एप्लिकेशन का क्या होगा। इन रिसावों का कारण क्या होगा? मैं अपने अंत में किसी भी गतिशील आवंटित वस्तुओं को हटा रहा हूं। साथ ही प्रोग्राम से बाहर निकलने पर मैं ऊपरी दाएं कोने में केवल बंद (एक्स) पर क्लिक करता हूं। क्या जीयूआई libs सिर्फ "मुक्त()" स्मृति में से कोई भी malloc() 'डी है?

Makefile qmake आदेश से घटाकर है:

####### 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 

एकमात्र स्रोत कोड है:

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(); 
} 

जब valgrind के माध्यम से चलाने मैं निम्नलिखित (निकाला गया बड़ा हिस्सा मध्य में) मिलता है:

==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

मैंने आपके छोटे एप्लिकेशन को संकलित किया और (दृश्य स्टूडियो क्रेट मेमोरीक डिटेक्टर का उपयोग करके) कोई मेमोरी लीक नहीं मिल सका। तो जो भी valgrind रिपोर्ट सीधे आपके कोड से संबंधित नहीं है।

हालांकि, एप्लिकेशन वास्तव में चलने से पहले आप QPushButton को हटा रहे हैं। आम तौर पर क्यूविंडोज़ के स्वामित्व को मूल विंडो में स्थानांतरित किया जाता है, इसलिए आपको ऑब्जेक्ट्स को स्वयं से साफ करने की आवश्यकता नहीं होती है, इसलिए माता-पिता विंडो आपके लिए हैंडल करती है (यदि ऐसा नहीं है, तो यह दस्तावेज़ीकरण में कहा गया है)।

तो, अपने कोड को सही करने के लिए, बस हटाएं हटाएं।