Subject: XDR and double data type
To: None <current-users@NetBSD.ORG>
From: Kent Vander Velden <>
List: current-users
Date: 06/05/1995 02:22:14
  A few months a go I sent a mail message about XDR not encoding
double's correctly.  I assumed the problem was fixed and had forgotten
about it until I spent an hour this evening tracking down a bug that
lead me to rediscover that XDR does not handle doubles properly.  I have
enclosed sample code to demonstrate this fact which seems to work fine
with OSF/1 v2.x and Ultrix 4.3 (in other words, I think the code is
"correct").  If I use the float data type the conversions seem to work
without fault.  The architecture that I have this problem on is the i386
architecture.  I will not bore you with my whining of how badly I need
this to work...


#include <stdio.h>
#include <stdlib.h>
#include <rpc/types.h>
#include <rpc/xdr.h>

main(void) {
  double x=3.14159;
  double y=0.0;
  char *xdr_buffer=NULL;
  XDR xdrs;
  int nbytes=1024; /*sizeof(double);*/

  xdr_buffer = (char*)malloc(nbytes);

  xdrmem_create(&xdrs, xdr_buffer, nbytes, XDR_ENCODE);
  xdr_double(&xdrs, &x);

  xdrmem_create(&xdrs, xdr_buffer, nbytes, XDR_DECODE);
  xdr_double(&xdrs, &y);


  printf("before encoding=%f\nafter encoding=%f\n", x, y);

  return 0;

Kent Vander Velden