take a const pointer in aghtmlstr

This function does not modify its string argument, so it is more accurate to
qualify it as const. Related to #634.

diff --git a/lib/cgraph/cgraph.h b/lib/cgraph/cgraph.h
index 9526ee3050721379d2b20f3f04edb1c37dfdf467..1e91f4a0f912663491964bc558ce1b75e17535f9 100644 (file)
--- a/lib/cgraph/cgraph.h
+++ b/lib/cgraph/cgraph.h
@@ -304,7 +304,7 @@ CGRAPH_API int agobjkind(void *);
 /* strings */
 CGRAPH_API char *agstrdup(Agraph_t *, const char *);
 CGRAPH_API char *agstrdup_html(Agraph_t *, const char *);
-CGRAPH_API int aghtmlstr(char *);
+CGRAPH_API int aghtmlstr(const char *);
 CGRAPH_API char *agstrbind(Agraph_t * g, char *);
 CGRAPH_API int agstrfree(Agraph_t *, char *);
 CGRAPH_API char *agcanon(char *, int);

diff --git a/lib/cgraph/refstr.c b/lib/cgraph/refstr.c
index e73c8cced38b5f3ae3a8d2be25848f23279ce813..d3317065d7d70c8abbfa1618725230e61d341aac 100644 (file)
--- a/lib/cgraph/refstr.c
+++ b/lib/cgraph/refstr.c
@@ -173,13 +173,13 @@ int agstrfree(Agraph_t * g, char *s)
  * Return true if s is an HTML string.
  * We assume s points to the datafield store[0] of a refstr.
  */
-int aghtmlstr(char *s)
+int aghtmlstr(const char *s)
 {
-    refstr_t *key;
+    const refstr_t *key;
 
     if (s == NULL)
        return 0;
-    key = (refstr_t *) (s - offsetof(refstr_t, store[0]));
+    key = (const refstr_t *) (s - offsetof(refstr_t, store[0]));
     return key->is_html;
 }