Bug#259318: pass by reference broken

[Alan <abgrover@cc.usu.edu>]

Package: g++-3.3
Version: 1:3.3.4-2

Pass by reference seems to be broken in g++.

Originally I thought the problem might be in ntohl, which is why it
appears in the test below.  However, the real problem seems to be in the
  mechanics of passing data.  A different variant of the program below
showed no problems in ntohl.  I also considered casting as the source of
the problem, but that also seems to work fine.

The program below gave the following output when compiled with g++-3.3
3.3.4 (Debian 1:3.3.4-2) :

alan@1[alan]$ ./testp
cast test: tmp is 4294967295, result is -1
ntohl test: result is -1

And the following correct output when compiled with g++-3.2 3.2.3 (Debian):

alan@1[alan]$ ./testp
cast test: tmp is 4294967295, result is -1
ntohl test: result is -6

This seems to show that result might have been passed by value instead
of by reference, since the value of result does not change.

Here is the test program:


// ------------begin test program---------------
#include <stdio.h>
#include <netinet/in.h>
#include <stdint.h>

uint32_t Read (uint32_t& v, char * buf);

int32_t Read (int32_t& v, char * buf);


int
main()
{
	char buffer[] = {
		255, 255, 255, 250  // -6 in network byte order
	};

	int32_t result = -1;
	uint32_t tmp = static_cast<uint32_t>(result);
	result = static_cast<int32_t>(tmp);

	printf("cast test: tmp is %u, result is %d\n", tmp, result);

	Read(result, buffer);
	printf("ntohl test: result is %d\n", result);
	return 0;
}


int32_t
Read(int32_t& v, char * buf)
{
	Read(static_cast<uint32_t>(v), buf);
	return v;
}

uint32_t
Read(uint32_t& v, char * buf)
{

	v = ntohl(*(reinterpret_cast<uint32_t*>(buf)));
	return v;

}
//------------end test program------------------------------