1 files changed, 2 insertions, 2 deletions
diff --git a/cpp/src/IceStorm/Service.cpp b/cpp/src/IceStorm/Service.cpp
index 4049b6b1017..519678d32b0 100644
--- a/cpp/src/IceStorm/Service.cpp
+++ b/cpp/src/IceStorm/Service.cpp
@@ -246,12 +246,12 @@ ServiceI::start(
                 // start of the node id, and then the end of the
                 // digits).
                 string::size_type start = instanceName.size();
-                while(start < adapterid.size() && !isdigit(adapterid[start]))
+                while(start < adapterid.size() && !isdigit(static_cast<unsigned char>(adapterid[start])))
                 {
                     ++start;
                 }
                 string::size_type end = start;
-                while(end < adapterid.size() && isdigit(adapterid[end]))
+                while(end < adapterid.size() && isdigit(static_cast<unsigned char>(adapterid[end])))
                 {
                     ++end;
                 }