problem with varargs.h in Xenix 2.3.3

[Perry L. Statham]

/*
Can anyone tell me why this program does not compile and how to fix it.

Operating System:
    SCO Xenix 2.3.3
    Dev Kit Release 2.3.0d
        
Compiler Message:
    testprog.c(19) : error 65: 'va_alist' : undefined

Line 19 is the line that has va_start on it.

The release lines for the two header files are:
    *	@(#) stdio.h 1.10 88/10/26 
    *	@(#) varargs.h 1.1 88/10/26 

Any help is appreciated.

Perry Statham
perry at statham.cactus.org
(512) 335-3881 (Home)
(512) 467-1396 (Work)

*/

#include <stdio.h>
#include <varargs.h>

void sceprintf( char *, 
                ... );  

main() {
  sceprintf("0x%x %d\n",1,1);
}

void sceprintf( format, ... )
char *format;
{
  FILE *log;
  va_list argptr;

  if ((log = fopen("logfile","a+")) != NULL) {
    va_start(argptr);
    vfprintf(log,format,argptr);
    va_end(argptr);
    fclose(log);
  }
}