diff --git a/tcc.h b/tcc.h
index fe870d8..48a42f2 100644
--- a/tcc.h
+++ b/tcc.h
@@ -1008,7 +1008,7 @@ PUB_FUNC void cstr_cat(CString *cstr, const char *str);
 PUB_FUNC void cstr_wccat(CString *cstr, int ch);
 PUB_FUNC void cstr_new(CString *cstr);
 PUB_FUNC void cstr_free(CString *cstr);
-#define cstr_reset(cstr) cstr_free(cstr)
+PUB_FUNC void cstr_reset(CString *cstr);
 
 ST_FUNC Section *new_section(TCCState *s1, const char *name, int sh_type, int sh_flags);
 ST_FUNC void section_realloc(Section *sec, unsigned long new_size);
diff --git a/tccpp.c b/tccpp.c
index b80c986..4b7b4fa 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -163,6 +163,12 @@ PUB_FUNC void cstr_free(CString *cstr)
     cstr_new(cstr);
 }
 
+/* reset string to empty */
+PUB_FUNC void cstr_reset(CString *cstr)
+{
+    cstr->size = 0;
+}
+
 /* XXX: unicode ? */
 static void add_char(CString *cstr, int c)
 {