diff --git a/source/iniparser/src/strlib.c b/source/iniparser/src/strlib.c
index 3bfddaaebe2..b954a36cf79 100644
--- a/source/iniparser/src/strlib.c
+++ b/source/iniparser/src/strlib.c
@@ -51,7 +51,7 @@
  */
 /*--------------------------------------------------------------------------*/
 
-char * strlwc(char * s)
+char * strlwc(const char * s)
 {
     static char l[ASCIILINESZ+1];
     int i ;
diff --git a/source/iniparser/src/strlib.h b/source/iniparser/src/strlib.h
index 8d8f15fcf0a..39ca26f1df0 100644
--- a/source/iniparser/src/strlib.h
+++ b/source/iniparser/src/strlib.h
@@ -45,7 +45,7 @@
   allocated, it will be modified at each function call (not re-entrant).
  */
 /*--------------------------------------------------------------------------*/
-char * strlwc(char * s);
+char * strlwc(const char * s);
 
 /*-------------------------------------------------------------------------*/
 /**