--- spack-src/plugins/macsio_silo.c.org	2020-02-04 10:48:08.031770849 +0900
+++ spack-src/plugins/macsio_silo.c	2020-02-04 10:48:48.175592435 +0900
@@ -706,7 +706,7 @@
     char fileName[256];
     MACSIO_MIF_baton_t *bat;
     MACSIO_MIF_ioFlags_t ioFlags = {MACSIO_MIF_WRITE,
-        JsonGetInt(main_obj, "clargs/exercise_scr")&0x1};
+        (unsigned int)JsonGetInt(main_obj, "clargs/exercise_scr")&0x1};
 
     /* Without this barrier, I get strange behavior with Silo's MACSIO_MIF interface */
 //#warning CONFIRM THIS IS STILL NEEDED