diff -Nur skycat-3.1.3.orig/cat/generic/TclAstroCat.C skycat-3.1.3/cat/generic/TclAstroCat.C
--- skycat-3.1.3.orig/cat/generic/TclAstroCat.C	2017-08-10 16:18:22.110000000 +0000
+++ skycat-3.1.3/cat/generic/TclAstroCat.C	2017-08-10 18:06:22.660000000 +0000
@@ -75,7 +75,7 @@
  */
 static class TclAstroCatSubCmds {
 public:
-    char* name;      // method name
+    const char* name;      // method name
     int (TclAstroCat::*fptr)(int argc, char* argv[]); 
     int min_args;    // minimum number of args
     int max_args;    // maximum number of args
diff -Nur skycat-3.1.3.orig/rtd/generic/BiasData.C skycat-3.1.3/rtd/generic/BiasData.C
--- skycat-3.1.3.orig/rtd/generic/BiasData.C	2017-08-10 16:18:22.120000000 +0000
+++ skycat-3.1.3/rtd/generic/BiasData.C	2017-08-10 18:05:35.520000000 +0000
@@ -76,7 +76,7 @@
 char* BiasData::file(int nr)
 {
     if (nr < 0 || nr >=MAXBIAS)
-	return '\0';
+	return "";
     return &files_[nr][0];
 }
 
diff -Nur skycat-3.1.3.orig/rtd/generic/RtdPerf.C skycat-3.1.3/rtd/generic/RtdPerf.C
--- skycat-3.1.3.orig/rtd/generic/RtdPerf.C	2017-08-10 16:18:22.120000000 +0000
+++ skycat-3.1.3/rtd/generic/RtdPerf.C	2017-08-10 18:05:35.520000000 +0000
@@ -226,18 +226,18 @@
     accGENtime_    = accTCLtime_ = accXtime_ = accFREQtime_ = 0.0;
 
     // Clear the Tcl variables.
-    Tcl_SetVar2(interp_, var, "PERF_COUNT",     '\0', TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_COUNT",     "", TCL_GLOBAL_ONLY);
 
-    Tcl_SetVar2(interp_, var, "PERF_FREQ",      '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_GEN",       '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_XFUNC",     '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_TCL",       '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_TOTAL",     '\0', TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_FREQ",      "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_GEN",       "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_XFUNC",     "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_TCL",       "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_TOTAL",     "", TCL_GLOBAL_ONLY);
 
-    Tcl_SetVar2(interp_, var, "PERF_FREQ_AVE",  '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_GEN_AVE",   '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_XFUNC_AVE", '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_TCL_AVE",   '\0', TCL_GLOBAL_ONLY);
-    Tcl_SetVar2(interp_, var, "PERF_TOTAL_AVE", '\0', TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_FREQ_AVE",  "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_GEN_AVE",   "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_XFUNC_AVE", "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_TCL_AVE",   "", TCL_GLOBAL_ONLY);
+    Tcl_SetVar2(interp_, var, "PERF_TOTAL_AVE", "", TCL_GLOBAL_ONLY);
 }