diff --git a/sim_fio.c b/sim_fio.c
index 455e2b2a..a5819d29 100644
--- a/sim_fio.c
+++ b/sim_fio.c
@@ -363,20 +363,15 @@ int sim_fseek (FILE *st, t_addr offset, int whence)
 return sim_fseeko (st, (t_offset)offset, whence);
 }
 
-int sim_set_fsize (FILE *fptr, t_addr size)
-{
-return sim_set_fsizeo (fptr, (t_offset)size);
-}
-
 #if defined(_WIN32)
 #include <io.h>
-int sim_set_fsizeo (FILE *fptr, t_offset size)
+int sim_set_fsize (FILE *fptr, t_addr size)
 {
-return _chsize_s(_fileno(fptr), (__int64)size);
+return _chsize(_fileno(fptr), (long)size);
 }
 #else /* !defined(_WIN32) */
 #include <unistd.h>
-int sim_set_fsizeo (FILE *fptr, t_offset size)
+int sim_set_fsize (FILE *fptr, t_addr size)
 {
 return ftruncate(fileno(fptr), (off_t)size);
 }
diff --git a/sim_fio.h b/sim_fio.h
index 4c7b43d7..9089a1f2 100644
--- a/sim_fio.h
+++ b/sim_fio.h
@@ -54,7 +54,6 @@ FILE *sim_fopen (const char *file, const char *mode);
 int sim_fseek (FILE *st, t_addr offset, int whence);
 int sim_fseeko (FILE *st, t_offset offset, int whence);
 int sim_set_fsize (FILE *fptr, t_addr size);
-int sim_set_fsizeo (FILE *fptr, t_offset size);
 size_t sim_fread (void *bptr, size_t size, size_t count, FILE *fptr);
 size_t sim_fwrite (void *bptr, size_t size, size_t count, FILE *fptr);
 uint32 sim_fsize (FILE *fptr);