diff -u -r -N a/src/exe/rbcavity.cxx b/src/exe/rbcavity.cxx
--- a/src/exe/rbcavity.cxx	2016-12-28 17:16:27.000000000 +0900
+++ b/src/exe/rbcavity.cxx	2021-02-01 20:14:47.508975264 +0900
@@ -50,7 +50,7 @@
 
 int main(int argc,const char* argv[])
 {
-	char 			c;					// for argument parsing
+	int 			c;					// for argument parsing
 	poptContext		optCon;				// ditto
 	char 			*prmFile=NULL;		// will be strReceptorPrmFile
 	char 			*listDist=NULL;		// will be 'dist' 
diff -u -r -N a/src/exe/rbdock.cxx b/src/exe/rbdock.cxx
--- a/src/exe/rbdock.cxx	2018-04-06 20:14:32.000000000 +0900
+++ b/src/exe/rbdock.cxx	2021-02-01 20:17:20.359974443 +0900
@@ -401,7 +401,7 @@
 	RbtInt		iTrace(0);//Trace level, for debugging
 
 	// variables for popt command-line parsing
-	char 			c;						// for argument parsing
+	int 			c;						// for argument parsing
 	
 #ifdef _VISUAL_STUDIO
 #else