diff --git a/service/ptos/head/ex/trace.h b/service/ptos/head/ex/trace.h
index d23a2ab..c1e5d38 100644
--- a/service/ptos/head/ex/trace.h
+++ b/service/ptos/head/ex/trace.h
@@ -12,6 +12,6 @@
 #include <lib/printf.h>
 
 #define TRACE       printf
-#define FmtPrintf   vsnprintf
+#define VFmtPrintf  vsnprintf
 
 #endif  /* !_EX_TRACE_H_ */