common: mark 'Arrowdirs' constant

diff --git a/lib/common/arrows.c b/lib/common/arrows.c
index e68f193cc650950301a2ed5735634a5098c895d5..4e342eed287bc0bff94107b992ddb6ba82e661bc 100644 (file)
--- a/lib/common/arrows.c
+++ b/lib/common/arrows.c
@@ -50,7 +50,7 @@ typedef struct arrowdir_t {
     int eflag;
 } arrowdir_t;
 
-static arrowdir_t Arrowdirs[] = {
+static const arrowdir_t Arrowdirs[] = {
     {"forward", ARR_TYPE_NONE, ARR_TYPE_NORM},
     {"back", ARR_TYPE_NORM, ARR_TYPE_NONE},
     {"both", ARR_TYPE_NORM, ARR_TYPE_NORM},
@@ -202,12 +202,11 @@ static void arrow_match_name(char *name, int *flag)
 void arrow_flags(Agedge_t * e, int *sflag, int *eflag)
 {
     char *attr;
-    arrowdir_t *arrowdir;
 
     *sflag = ARR_TYPE_NONE;
     *eflag = agisdirected(agraphof(e)) ? ARR_TYPE_NORM : ARR_TYPE_NONE;
     if (E_dir && ((attr = agxget(e, E_dir)))[0]) {
-       for (arrowdir = Arrowdirs; arrowdir->dir; arrowdir++) {
+       for (const arrowdir_t *arrowdir = Arrowdirs; arrowdir->dir; arrowdir++) {
            if (streq(attr, arrowdir->dir)) {
                *sflag = arrowdir->sflag;
                *eflag = arrowdir->eflag;