bryan@UUNET.UU.NET (Bryan Boreham) (06/21/89)
Here's the example:
extern "C" void printf(char *, ...);
class Point
{
public:
short x;
short y;
public:
Point(short xx, short yy)
{ x= xx; y= yy; }
friend Point operator- (Point p1, Point p2)
{ return Point(p1.x - p2.x, p1.y - p2.y); }
};
void foo (Point p)
{
printf("(%d, %d)\n", p.x, p.y);
}
main()
{
Point x(10,20);
Point y(30,40);
foo (x - y);
}
Now, it compiles just fine:
kewill% g++ -v testpt.C -o testpt
g++ version 1.35.1-
/usr/local/lib/gcc-cpp -+ -v -undef -D__GNU__ -D__GNUG__ -D__cplusplus -Dmc68000 -Dsun -Dunix -D__mc68000__ -D__sun__ -D__unix__ -D__HAVE_68881__ -Dmc68020 testpt.C /tmp/cca29165.cpp
GNU CPP version 1.35
/usr/local/lib/gcc-cc1plus /tmp/cca29165.cpp -quiet -dumpbase testpt.C -noreg -version -o /tmp/cca29165.s
GNU C++ version 1.35.1- (68k, MIT syntax) compiled by GNU C version 1.35.
as -mc68020 /tmp/cca29165.s -o testpt.o
/usr/local/lib/gcc-ld++ -o testpt -C /usr/local/lib/crt0+.o /lib/Mcrt1.o testpt.o -lg++ /usr/local/lib/gcc-gnulib -lc
But, it gets the answer wrong!
kewill% testpt
(0, 40)
Now, I looked through Stroustrup and libg++, and I only ever see such
operators declared as:
friend Point operator- (Point& p1, Point& p2)
that is, with references instead of structures passed. So maybe there
is some reason why the answer is wrong.
Nonetheless, I think it ought to work.
Say, isn't ET++ good at flushing out those bugs?
Bryan.tom@tnosoes.UUCP (Tom Vijlbrief) (06/21/89)
I mailed an almost identical bug report yesterday to Michael Tieman. A fix is to use -fno-defer-pop when compiling ! Tom =============================================================================== Tom Vijlbrief TNO Institute for Perception P.O. Box 23 Phone: +31 34 63 562 11 3769 ZG Soesterberg E-mail: tnosoes!tom@mcvax.cwi.nl The Netherlands or: uunet!mcvax!tnosoes!tom ===============================================================================