bug report

[GAMMELJL]

//Here, as simply as I can put it, is a bug (?) having to do with
//trying to set an mpf_t (which is a member of a class) inside a
//subroutine:  The notes are contained in cout statements (so that 
//the notes will appear on the screen if the code below is compiled
//and run).
//If you do not wish to compile and run the code below, start
//reading cout at POINT1 below, then from POINT2 to POINT3, and
//finally at POINT4 to the end.

//Data you asked for:  version: gmp-3.1
//                     compiler: g++
//                compiled with: g++ code.cpp -o code -lgmp 
//           output of uname -a: 
//localhost.localdomain 2.0.35 #1 Tue July 14 23:56:59 EDT 1998
//                                                i 686 unknown             

#include <iostream.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "gmp.h"
#include "gmp-impl.h"

class realmp{
public:
  mpf_t s;
  realmp();
};

realmp::realmp()
{mpf_init2(s,1695);
 mpf_set_si(s,-777);}

realmp a;              

void zfcn(realmp ww8)
   {cout<<"a.s in zfcn before ww8.s is set "; mpf_dump(a.s);//POINT2
    cout<<"which is what it was set to in realmp() when"<<'\n';
    cout<<"a was declared, and that is correct."<<'\n';
    cout<<"ww8.s in zfcn before ww8.s is set ";mpf_dump(a.s);
    cout<<"which is likewise correct."<<'\n';
    cout<<"Now set ww8.s to 88:"<<'\n';
    mpf_set_si(ww8.s,88);
    cout<<"Notice that ww8.s is set correctly in zfcn: "; 
    mpf_dump(ww8.s);
    cout<<"But, a.s in zfcn after ww8.s is set,"<<'\n';
    cout<<"ought to be the same thing as ww8.s, which it is"<<'\n'; 
    cout<<"except it has the wrong sign: ";                //POINT3
    mpf_dump(a.s);                    
   }
                                              
main() 
  {cout<<'\n';                               
   cout<<"Try to set a.s to 88 using zfcn:"<<'\n';         //POINT1
   zfcn(a);                  
   cout<<"and this wrong sign is returned to main: "<<'\n';//POINT4
   mpf_dump(a.s);                                             
   cout<<'\n';
   cout<<"The bug (?) is: what happened to the sign?"<<'\n';
   cout<<'\n';
   cout<<"Change the -777 to +777 and the sign will come"<<'\n'; 
   cout<<"out ok, but that begs the question.  Change the"<<'\n';
   cout<<"-777 to 0 and the result will be 0. "<<'\n';
   cout<<'\n';
   return 0;
  }