const char S_ERRORSTR[] = "error string";
const char S_FMTERR[] = "%s %.3f %.3f";
...
throw MyException(S_ERRORSTR);
...
throw MyException(S_FMTERR, x, y);

class Exception : public QException {
protected:
    String f_message;
public:
    Exception(const char fmt[], const void *[]) { .............. }

#ifndef RC_STRINGS_H
#define RC_STRINGS_H
#include <QString>

static const QString testString = "Test string";

ххххх\rc_strings.h:5:1: non-POD static (QString) [clazy-non-pod-global-static]

public:
    Exception(const char msg[]) { f_message = String::fromUtf8(msg); }
    Exception(const char *cformat, ...)  { .... }

const QString S_ERR_CONFIGISMISSING = "Не задана конфигурация";

class myException : public QException {
    myException(const char msg[]) {f_msg = QString::fromUtf8(msg);}
public:
    QString message();
    void raise() const override { throw *this; }
    Exception *clone() const override { return new MyException(*this); }
private:
    QString f_msg;
};

throw myException("some text");

    try {
      ...........
    } catch (myException e) {
        QMessageBox::critical(&w,
                              "Ошибка",
                              e.message());
        return 1;
    }
}

{ return new myException(this.message().toUTF8()); }