diff --git a/src/tool/tool.c b/src/tool/tool.c
index fa69ffb1..9e290749 100644
--- a/src/tool/tool.c
+++ b/src/tool/tool.c
@@ -186,7 +186,7 @@ CODE facilitynames[] = {
 #endif
 
 
-GLOBAL char
+GLOBAL const char
 *ngt_SyslogFacilityName(int Facility)
 {
 	int i = 0;
diff --git a/src/tool/tool.h b/src/tool/tool.h
index ea9e96b9..4513a232 100644
--- a/src/tool/tool.h
+++ b/src/tool/tool.h
@@ -30,7 +30,7 @@ GLOBAL char *ngt_UpperStr PARAMS((char *String ));
 GLOBAL char *ngt_LowerStr PARAMS((char *String ));
 
 #ifdef SYSLOG
-GLOBAL char *ngt_SyslogFacilityName PARAMS((int Facility));
+GLOBAL const char *ngt_SyslogFacilityName PARAMS((int Facility));
 GLOBAL int ngt_SyslogFacilityID PARAMS((char *Name, int DefaultFacility));
 #endif