From:	ranla AT post DOT tau DOT ac DOT il (Tal Lavi)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Works on WATCOM, doesn't work on DJGPP?
Date:	Fri, 27 Nov 1998 15:39:52 LOCAL
Organization:	Tel-Aviv University Computation Center
Lines:	59
Message-ID:	<ranla.126.000B98BD@post.tau.ac.il>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Hello,

I'm using DJGPP 2.81, under DOS.

I wanted to overload the = operator for my fixed point class, as seen in
another class I download somewhere, that was meant for compiling under WATCOM.

inline fixed &operator= (int a) {value = long(a)<<16;return *this;}

As copied for the class's documentation:

"In general, there are four of each operation , one each for fixed,
int, float and double. Thankfully, Watcom will automatically cast
any other ordinal types (short, long, char, unsigned int, etc.) to int."

I was very disapointed to see that DJGPP does not have that quality!
A simple test program compiles fine when using ints, but gives me errors for
unknown combination of operands if I use unsigned longs.

Does this is a true DJGPP flaw? 
Is there a way(that will work under DJGPP, ofcourse) to overload 
the =,+,-,*,/ operators so that every combination of fixed point, ordinal
types, floats and doubles can be used?(also: int=Fixed, float=Fixed)

Below is a minimal class and test program(in one file), that contains this problem.

#include <stdio.h>
#include <conio.h>

class Fixed
{
public:
  signed long data;

  Fixed(void){}
  Fixed(int x){data=(signed long)(x)<<16;}
  Fixed(float x){data=(signed long)(x*65536.0+0.5);}
  Fixed(double x){data=(signed long)(x*65536.0+0.5);}

  Fixed &operator=(Fixed const &x){data=x.data;                return *this;}
  Fixed &operator=(int x)   {data=(signed long)(x)<<16;        return *this;}
  Fixed &operator=(float x) {data=(signed long)(x*65536.0+0.5);return *this;}
  Fixed &operator=(double x){data=(signed long)(x*65536.0+0.5);return *this;}
};

int main()
{
  Fixed a;
  int b=1;
  signed long c=2;
  a=b;//compiles OK
  a=c;//compile errors
  return(0);
}


	Thanks in advance,

		Tal Lavi		ranla AT post DOT tau DOT ac DOT il

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