#define PerlIO_fileno(f) sffileno(f)
#define PerlIO_clearerr(f) sfclrerr(f)
#define PerlIO_flush(f) sfsync(f)
-#define PerlIO_tell(f) sftell(f)
+#define PerlIO_tell(f) sfseek(f,0,1|SF_SHARE)
#define PerlIO_seek(f,o,w) sfseek(f,o,w)
#define PerlIO_rewind(f) (void) sfseek((f),0L,0)
#define PerlIO_tmpfile() sftmp(0)