Program terminated with signal 11, Segmentation fault.
空指针访问非虚函数
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| include <iostream>
class Foo
{
public:
Foo() : a(0) {}
void Bar() { std::cout << "Bar:" << a << std::endl; }
private:
int a;
};
int main() {
Foo* f = NULL;
f->Bar();
std::cout << "hello" << std::endl;
return 0;
}
|
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| (gdb) bt
#0 0x00000000004008ef in Foo::Bar (this=0x0) at null.cpp:6
#1 0x00000000004008bb in main () at null.cpp:14
(gdb)
|
空指针访问虚函数
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| #include <iostream>
class Foo
{
public:
Foo() : a(0) {}
virtual void Bar() { std::cout << "Bar:" << a << std::endl; }
private:
int a;
};
int main() {
Foo* f = NULL;
f->Bar();
std::cout << "hello" << std::endl;
return 0;
}
|
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| (gdb) bt
#0 0x0000000000400866 in main () at null.cpp:14
(gdb) p f
$1 = (Cannot access memory at address 0x0
|
野指针访问虚函数
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| #include <iostream>
class Foo
{
public:
Foo() : a(0) {}
virtual void Bar() { std::cout << "Bar:" << a << std::endl; }
private:
int a;
};
int main() {
Foo* f = new Foo();
delete f;
f->Bar();
std::cout << "hello" << std::endl;
return 0;
}
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| (gdb) bt
#0 0x00000000004009c4 in main () at null.cpp:15
(gdb) p f
$1 = (Foo *) 0x602010
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