func(" ") causes "call of overloaded QChar(const char[2]) is ambiguous

Can tell me why the code below causes this error :

call of overloaded 'QChar(const char[2])' is ambiguous  

and the code :

void func(QChar a) {
    qDebug() << a;
}

void main() {
    func(" ");
}

When String.remove(QChar,Qt::Ca开发者_开发知识库seSensitive) works : a.remove(" ");

You're passing a string literal (" "), which is of type const char[2] (one element containing the space, and another one for the terminating \0). You want to pass a char literal, written with single quotes: func(' ').

The QString::remove() function is overloaded for both strings and single characters. Even in that case, you want to pass a char literal ' ', which is more efficient than " " (the latter implies a call to strlen()).

Try to write

void main() {
  func(' ');
}

Seems like compiler thinks that you passing const char* not a char because of double quotes. And there is no constructor for QChar from const char*.