QString fromStdString静态函数而不是构造函数

Question

What is the reason for the choice of API below:

QString QString::fromStdString(const std::string & str) [static]

Why is there a need for calling a static function when we could have a constructor as follows:

QString::QString(const std::string & str)

There are similar constructors for the c string representation (char*), std::string being the exception. What is the reason for that?

Answer 1

Qt predates explicit constructors, and it can't break its existing clients gratuitously. One other reason would be that std::string and QString are not necessarily in the same encoding/codepage and the static methods make explicit that some more expensive conversion is happening.