Seek in correct file.
diff --git a/lib/zip_source_file_win32.c b/lib/zip_source_file_win32.c
index 1e83bcb..ba3bfff 100644
--- a/lib/zip_source_file_win32.c
+++ b/lib/zip_source_file_win32.c
@@ -117,8 +117,8 @@
     }
 
     li.QuadPart = (LONGLONG)offset;
-    if (!SetFilePointerEx((HANDLE)ctx->f, li, NULL, method)) {
-    zip_error_set(&ctx->error, ZIP_ER_SEEK, _zip_win32_error_to_errno(GetLastError()));
+    if (!SetFilePointerEx((HANDLE)f, li, NULL, method)) {
+        zip_error_set(&ctx->error, ZIP_ER_SEEK, _zip_win32_error_to_errno(GetLastError()));
         return false;
     }