I believe you are supplying the wrong parameters.
It seems the output structure consists of an integer followed
by the sysname; you probably ran it on a big-endian
machine, so the first (high) byte of the output integer
was 0 - a null string.
I found a test program that happens to use just this: (the
use of lpioctl is because I didn't care if it couldn't run on an
NFS client...)
=============== sy.c
#include <afs/param.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <afs/venus.h>
main()
{
struct ViceIoctl blob;
struct {
int32 setp;
char data[512];
} space;
long code;
space.setp = 0;
blob.in = (char*)&space;
blob.out = (char*)&space;
blob.out_size = sizeof space;
blob.in_size = sizeof space.setp;
code = lpioctl(0, VIOC_AFS_SYSNAME, &blob, 1);
if (code)
printf ("sysname failed: %s\n", error_message(code));
else if (!space.setp)
printf ("no sysname value was found\n");
else printf ("Current sysname is <%s>\n", space.data);
exit(0);
}
=============== Makefile
AFS=your AFS client library & include area/
sy: sy.o
cc -o sy sy.o ${AFS}lib/afs/libsys.a ${AFS}lib/afs/libcom_err.a
sy.o: sy.c
cc -I${AFS}include -c afs sy.c
===============
-Marcus
