vslprintf
(void) vslprintf(buf + i, sizeof (buf) - i, fmt, args);
extern int vslprintf __P((char *, int, const char *, va_list));/* vsprintf++ */
n = vslprintf(buf, buflen, fmt, args);
n = vslprintf(buf, sizeof (buf), fmt, args);
n = vslprintf(bi->ptr, bi->len, fmt, pvar);
n = vslprintf(buf, sizeof(buf), fmt, pvar);
n = vslprintf(buf, sizeof(buf), fmt, args);