std::string 在参数中构造

我遇到了一个非常棘手的C++编译器错误。

当我构造一个字符串以用作参数时，它在调用常规方法时有效。 例如 printThisString(string(charPtr));

如果构造函数的参数是char*，则在构造对象时它不起作用。例如，如果参数是文字，MyObject a(string(argv[0]));它仍然有效。例如，MyObject b(string("hi"));

#include <iostream>
#include <string>
using namespace std;
void printString(string toPrint) {
    cout << toPrint << endl;
}
class MyObject {
    int blah;
public:
    void aMethod() {}
    MyObject (string myStr) {
        cout << myStr << endl;
    }
};
int main(int argc, char ** argv) {
string s1(argv[0]);
char * s2 = "C-style string"; // I realize this is bad style
printString(string("Hello world!")); // All of these work
printString(s1);
printString(string(s2));
printString(string(argv[0]));
MyObject mo1 (string("Hello world!")); // Valid
MyObject mo2 (s1); // Valid
MyObject mo3 (string(s2)); // Does not print
MyObject mo4 (string(argv[0])); // Does not print
mo1.aMethod();
mo2.aMethod();
mo3.aMethod(); // Error
mo4.aMethod(); // Error

return 0;
}

对于 mo3 和 mo4，可以创建对象，但不能使用任何方法。它们属于错误的类型。编译器似乎认为它们是函数...

test.cpp: In function 'int main(int, char**)':
test.cpp:22:13: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
test.cpp:36:5: error: request for member 'aMethod' in 'mo3', which is of non-class type 'MyObject(std::string) {aka MyObject(std::basic_string<char>)}'
test.cpp:37:5: error: request for member 'aMethod' in 'mo4', which is of non-class type 'MyObject(std::string*) {aka MyObject(std::basic_string<char>*)}'