diff --git a/unzip/ioapi.cpp b/unzip/ioapi.cpp
index 7898b2804..161718bdf 100644
--- a/unzip/ioapi.cpp
+++ b/unzip/ioapi.cpp
@@ -111,7 +111,7 @@ static voidpf ZCALLBACK fopen64_file_func (voidpf opaque, const void* filename,
 
     if ((filename!=NULL) && (mode_fopen != NULL))
     {
-        file = fopen64((const char*)filename, mode_fopen);
+        file = fopen((const char*)filename, mode_fopen);
     }
 
     return file;
@@ -143,7 +143,7 @@ static long ZCALLBACK ftell_file_func (voidpf opaque, voidpf stream)
 static ZPOS64_T ZCALLBACK ftell64_file_func (voidpf opaque, voidpf stream)
 {
     ZPOS64_T ret;
-    ret = ftello64((FILE *)stream);
+    ret = ftello((FILE *)stream);
     return ret;
 }
 
@@ -186,7 +186,7 @@ static long ZCALLBACK fseek64_file_func (voidpf  opaque, voidpf stream, ZPOS64_T
         break;
     default: return -1;
     }
-    if(fseeko64((FILE *)stream, offset, fseek_origin) != 0)
+    if(fseeko((FILE *)stream, offset, fseek_origin) != 0)
         return -1;
     return 0;
 }