diff --git a/src/libCom/env/envDefs.h b/src/libCom/env/envDefs.h
index 0c5f400be..9c0e7bcf7 100644
--- a/src/libCom/env/envDefs.h
+++ b/src/libCom/env/envDefs.h
@@ -99,7 +99,7 @@ epicsShareFunc const char * epicsShareAPI
 epicsShareFunc unsigned short epicsShareAPI envGetInetPortConfigParam 
         (const ENV_PARAM *pEnv, unsigned short defaultPort);
 epicsShareFunc long epicsShareAPI epicsPrtEnvParams(void);
-epicsShareFunc void epicsShareAPI epicsEnvSet (char *name, char *value);
+epicsShareFunc void epicsShareAPI epicsEnvSet (const char *name, const char *value);
 epicsShareFunc void epicsShareAPI epicsEnvShow (const char *name);
 
 #ifdef __cplusplus
diff --git a/src/libCom/osi/os/default/osdEnv.c b/src/libCom/osi/os/default/osdEnv.c
index 0ea40e1a5..27d016fc8 100644
--- a/src/libCom/osi/os/default/osdEnv.c
+++ b/src/libCom/osi/os/default/osdEnv.c
@@ -31,7 +31,7 @@
  * Leaks memory, but the assumption is that this routine won't be
  * called often enough for the leak to be a problem.
  */
-epicsShareFunc void epicsShareAPI epicsEnvSet (char *name, char *value)
+epicsShareFunc void epicsShareAPI epicsEnvSet (const char *name, const char *value)
 {
     char *cp;
 
diff --git a/src/libCom/osi/os/vxWorks/osdEnv.c b/src/libCom/osi/os/vxWorks/osdEnv.c
index 5251448c7..40bd56511 100644
--- a/src/libCom/osi/os/vxWorks/osdEnv.c
+++ b/src/libCom/osi/os/vxWorks/osdEnv.c
@@ -32,7 +32,7 @@
  * Leaks memory, but the assumption is that this routine won't be
  * called often enough for the leak to be a problem.
  */
-epicsShareFunc void epicsShareAPI epicsEnvSet (char *name, char *value)
+epicsShareFunc void epicsShareAPI epicsEnvSet (const char *name, const char *value)
 {
     char *cp;