diff --git a/src/smart-parser.c b/src/smart-parser.c
index de9885b0..795d637e 100644
--- a/src/smart-parser.c
+++ b/src/smart-parser.c
@@ -710,7 +710,7 @@ PARSETREE sp_init(void) {
  * @param term term or phrase to parse
  * @returns 1 if successful, 0 if not
  */
-int sp_parse(PARSETREE tree, char *term, int type) {
+int sp_parse(PARSETREE tree, const char *term, int type) {
     tree->term = strdup(term); /* will be destroyed by parsing */
     tree->current=tree->term;
     tree->token.token_id=T_BOF;
diff --git a/src/smart-parser.h b/src/smart-parser.h
index d4421ee4..2b32256f 100644
--- a/src/smart-parser.h
+++ b/src/smart-parser.h
@@ -5,7 +5,7 @@
 typedef void* PARSETREE;
 
 extern PARSETREE sp_init(void);
-extern int sp_parse(PARSETREE tree, char *term, int type);
+extern int sp_parse(PARSETREE tree, const char *term, int type);
 extern int sp_dispose(PARSETREE tree);
 extern char *sp_get_error(PARSETREE tree);
 extern char *sp_sql_clause(PARSETREE tree);