Subject: Problem with libgtop2
To: None <>
From: Julio M. Merino Vidal <>
List: tech-userlevel
Date: 04/12/2004 14:49:13
Hi all,

[ posting to -userlevel because this is not exactly a packages question ]

I've found a problem in libgtop2, where it doesn't pass parameters correctly
between some functions.  Consider the following test case (which, aside from
the 'buf' thing does the same as libgtop2):

#include <sys/types.h>
#include <stdio.h>

void foo(void *ptr)
    int64_t *params = (int64_t *)ptr;
    printf("arg1: %d\n", params[0]);
    printf("arg2: %d\n", params[1]);

void func(int64_t a, int64_t b)
    int64_t buf[2];

    foo((void *)&a); /* This is what libgtop does */

    buf[0] = a;
    buf[1] = b;
    foo((void *)&buf);

int main(void) {
    func((int64_t) 10, (int64_t) 20);
    return 0;

Which outputs:

arg1: 10
arg2: 1208273232
arg1: 10
arg2: 20

Note the second line, which shows an incorrect value, just like libgtop2.

Using 'long' instead of int64_t, works.  This same program works properly
under linux.

What's happening here?  I can't figure it out :(


Julio M. Merino Vidal <>
The NetBSD Project -