[英]Valgrind and ostream operator
Why is Valgrind showing error in this code?为什么 Valgrind 在这段代码中显示错误?
// const char * constructor
String::String(const char* s) {
size = 0;
while(s[size] != '\0')
++size;
capacity = 0;
str = new char[size];
for (int i = 0; i < size; ++i) {
str[i] = s[i];
if (size > capacity && capacity == 0) {
++capacity;
} else if ((size > capacity && capacity != 0)) {
capacity *= 2;
}
}
}
// overloading the ostream operator
std::ostream &operator<<(std::ostream &os, const String& other) {
return std::operator<<(os, other.str);
}
// testing
TEST(Iostream, Out) {
std::stringstream os;
String s = "lol";
os << s;
ASSERT_EQ(os.str(), "lol");
}
// main function for testing
int main() {
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
//////////////////////////////////////////////////////////////// Why is strlen showing here if I haven't used it anywhere? ///////////////////////////////////////////////// ///////////// 如果我没有在任何地方使用过 strlen 为什么会在这里显示?
==11274== Invalid read of size 1
==11274== at 0x48425F4: strlen (vg_replace_strmem.c:469)
==11274== by 0x49BCBCD: std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.28)
Why is strlen showing here if I haven't used it anywhere?如果我没有在任何地方使用过 strlen,为什么会在此处显示?
return std::operator<<(os, other.str);
This is the same function that is called when you do:这与您执行以下操作时调用的函数相同:
void foo(std::ostream& stream, const char * ptr) {
stream << ptr;
}
How else is the stream supposed to know the length of the passed null-terminated string if not via a strlen()
or something equivalent?如果不是通过strlen()
或等效的东西,流应该如何知道传递的以空字符结尾的字符串的长度?
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