semihc / qdecimal Goto Github PK

Reported by Aleksey Sukhonosov:

Please, take a look at the code:

    QDecNumber i;
    i.fromString("1.125");
    qDebug()<<i.toString()<<"~"<<QString::number(i.toDouble(),'f',2)<<" or "<<QString::number(QString("1.125").toDouble(),'f',2)<<" or "<<QString::number(QString(i.toString()).toDouble(),'f',2);
    i.fromString("1.375");
    qDebug()<<i.toString()<<"~"<<QString::number(i.toDouble(),'f',2)<<" or "<<QString::number(QString("1.375").toDouble(),'f',2)<<" or "<<QString::number(QString(i.toString()).toDouble(),'f',2);

The output should contain an original number and this number having been 
rounded. Every rounding method is supposed to give the same result. But in 
debug I have:

"1.125" ~ "1.00"  or  "1.12"  or  "1.12" 
"1.375" ~ "1.00"  or  "1.38"  or  "1.38" 

So, it seems that QDecNumber::toDouble() works in a wrong way, as everything it 
returns is of integer value (though, of double type).

In
     int QDecNumberTests::opTest(const QStringList& tokens)    
it says
    /* Uncomment to receive more information about passing test cases: */
but it seems there is nothing to uncomment. Is this way?    

Thanks for QDecimal! 

> What steps will reproduce the problem?

I compiled
      QDecDouble num("0.1");
      QDecDouble aux = 1 + num;
      cout << aux << endl;
and the result was
        8.19999E-393
which is very close to zero, which is not adequate. 

However, I compiled 
        double num(0.1);
        double aux = 1 + num;
        cout << aux << endl;
and the result was 
        1.1
which is correct. I obtained the same result using "qreal" instead of "double", 
of course.

> What version of the product are you using? On what operating system?
QDecimal 1.0.1. Kubuntu 13.04.

Thanks for QDecimal! 

When compiling Main.cc, `gcc` emits a warning about
    void MessageOutput(QtMsgType type, const QMessageLogContext &context,
                        const QString &msg)
and its variable "context" that is never used. 

That puzzles the developers ("A warning?" "What's happening?" "Is QDecimal well 
done?" "Should I solve it?" "Can I solve it?" "Should I file a bug?"). I read 
<http://dbp-consulting.com/tutorials/SuppressingGCCWarnings.html> and added 
three "pragmas" in my local QDecimal copy, this way:

    [...]
    #pragma GCC diagnostic push
    #pragma GCC diagnostic ignored "-Wunused-parameter"
    void MessageOutput(QtMsgType type, const QMessageLogContext &contexte,
                        const QString &msg)
    {

    QByteArray lmsg = msg.toLocal8Bit();
    const char* cmsg = lmsg.constData();
    switch (type) {
        case QtDebugMsg:
        fprintf(stderr, "%s\n", cmsg);
        break;
        case QtWarningMsg:
        fprintf(stderr, "Warn: %s\n", cmsg);
        break;
        case QtCriticalMsg:
        fprintf(stderr, "Critical: %s\n", cmsg);
        break;
        case QtFatalMsg:
        fprintf(stderr, "Fatal: %s\n", cmsg);
        abort();
    }
    }
    #pragma GCC diagnostic pop
    [...]

and this way `gcc` doesn't warn about "unused parameters", but probably you'll 
have a better solution to avoid warning developers (`gcc` ones, at least).

Thanks for QDecimal! 

What steps will reproduce the problem?
1. Attempt to instantiate a QDecNumber object from DBL_MAX double value.

QDecNumber decNum(DBL_MAX);

2. Compile and run program.

What is the expected output?

1.7976931348623158e+308

What do you see instead?

Program crashes.

What version of the product are you using? On what operating system?

1.0.0

Please provide any additional information below.

The problem stems from the fact that MaxStrSize is too small to accommodate all 
representable doubles in the 'f' format specified in sprintf(str,'%f',d) in 
fromDouble.  Changing the format specifier to '%.16e' seems to resolve the 
issue, the only downside being the forced precision of 16 decimal digits when 
that might not always be the desired precision.

What steps will reproduce the problem?
1. Type nmake in any directory and receive error msg
"NMAKE : fatal error U1064: MAKEFILE not found and no target specified
Stop."
2. Type nmake *.pri or *.pro and all one receives is errors,
generally of the form "Too many names to left of =" wherever a +=
token appears.

What is the expected output? What do you see instead?
Trying to compile under MS VCC; nothing happens.

What version of the product are you using? 
Product: Microsoft Visual Studio Express 2012 for Windows Desktop
O/S: Windows 8

Please provide any additional information below.
In trying to compile "Example 1" under MS Viual Studio Express 2012 I get these 
5 errors:
Error   14  error LNK2001: unresolved external symbol "struct decContext * __cdecl 
decContextDefault(struct decContext *,int)" 
(?decContextDefault@@YAPAUdecContext@@PAU1@H@Z) 

Error   15  error LNK2001: unresolved external symbol "struct decNumber * __cdecl 
decNumberFromString(struct decNumber *,char const *,struct decContext *)" 
(?decNumberFromString@@YAPAUdecNumber@@PAU1@PBDPAUdecContext@@@Z)

Error   16  error LNK2001: unresolved external symbol "struct decNumber * __cdecl 
decNumberAdd(struct decNumber *,struct decNumber const *,struct decNumber const 
*,struct decContext *)" 
(?decNumberAdd@@YAPAUdecNumber@@PAU1@PBU1@1PAUdecContext@@@Z)

Error   17  error LNK2001: unresolved external symbol "char * __cdecl 
decNumberToString(struct decNumber const *,char *)" 
(?decNumberToString@@YAPADPBUdecNumber@@PAD@Z)

Error   18  error LNK1120: 4 unresolved externals

256 bytes is not enough to represent a double number of DBL_MAX or DBL_MIN

try this,

int main(int argc, char *argv[])
{    
    double d = DBL_MAX;
    QDecDouble dd(d);
}

and see the application happily crash.

What steps will reproduce the problem?
1. Qmake -r
2. mingw32-make


What is the expected output? What do you see instead?
Compiled library

What version of the product are you using? On what operating system?
QT4.8 command prompt

Please provide any additional information below.

g++: /Zc:forScope: No such file or directory
g++: /Zc:wchar_t: No such file or directory
g++: /RTC1: No such file or directory
mingw32-make[2]: *** [debug/QDecContext.o] Error 1
mingw32-make[2]: Leaving directory `D:/Lähdekoodeja/qdecimal/src'
mingw32-make[1]: *** [debug] Error 2
mingw32-make[1]: Leaving directory `D:/Lähdekoodeja/qdecimal/src'
mingw32-make: *** [sub-src-make_default-ordered] Error 2