clang warnings in regcomp.c

clang warnings in regcomp.c

[Bruno Haible]

clang produces these warning about regcomp.c:

regcomp.c(40,25): warning: redundant parentheses surrounding declarator [-Wredundant-parens]
regcomp.c(43,19): warning: redundant parentheses surrounding declarator [-Wredundant-parens]
regcomp.c(1226,44): warning: redundant parentheses surrounding declarator [-Wredundant-parens]
regcomp.c(1258,43): warning: redundant parentheses surrounding declarator [-Wredundant-parens]

What is the point of these parentheses?

Would this patch be OK (also in glibc)?


diff --git a/lib/regcomp.c b/lib/regcomp.c
index 692928b..392d125 100644
--- a/lib/regcomp.c
+++ b/lib/regcomp.c
@@ -37,10 +37,10 @@ static void optimize_utf8 (re_dfa_t *dfa);
 #endif
 static reg_errcode_t analyze (regex_t *preg);
 static reg_errcode_t preorder (bin_tree_t *root,
-			       reg_errcode_t (fn (void *, bin_tree_t *)),
+			       reg_errcode_t fn (void *, bin_tree_t *),
 			       void *extra);
 static reg_errcode_t postorder (bin_tree_t *root,
-				reg_errcode_t (fn (void *, bin_tree_t *)),
+				reg_errcode_t fn (void *, bin_tree_t *),
 				void *extra);
 static reg_errcode_t optimize_subexps (void *extra, bin_tree_t *node);
 static reg_errcode_t lower_subexps (void *extra, bin_tree_t *node);
@@ -1223,7 +1223,7 @@ analyze (regex_t *preg)
    implement parse tree visits.  Instead, we use parent pointers and
    some hairy code in these two functions.  */
 static reg_errcode_t
-postorder (bin_tree_t *root, reg_errcode_t (fn (void *, bin_tree_t *)),
+postorder (bin_tree_t *root, reg_errcode_t fn (void *, bin_tree_t *),
 	   void *extra)
 {
   bin_tree_t *node, *prev;
@@ -1255,7 +1255,7 @@ postorder (bin_tree_t *root, reg_errcode_t (fn (void *, bin_tree_t *)),
 }
 
 static reg_errcode_t
-preorder (bin_tree_t *root, reg_errcode_t (fn (void *, bin_tree_t *)),
+preorder (bin_tree_t *root, reg_errcode_t fn (void *, bin_tree_t *),
 	  void *extra)
 {
   bin_tree_t *node;

Re: clang warnings in regcomp.c

[Paul Eggert]

On 9/6/20 5:45 PM, Bruno Haible wrote:

> What is the point of these parentheses?

Haven't a clue. It's an unusual style.

>   static reg_errcode_t preorder (bin_tree_t *root,
> -			       reg_errcode_t (fn (void *, bin_tree_t *)),
> +			       reg_errcode_t fn (void *, bin_tree_t *),
>   			       void *extra);

For corrections like that I suggest the style "reg_errcode_t (*fn) (void *, 
bin_tree_t *)" instead, as that's the usual style in glibc and I expect it is 
the style that was intended in regcomp.c anyway.

Re: clang warnings in regcomp.c

[Bruno Haible]

Paul Eggert wrote:
> > What is the point of these parentheses?
> 
> Haven't a clue. It's an unusual style.
> 
> >   static reg_errcode_t preorder (bin_tree_t *root,
> > -			       reg_errcode_t (fn (void *, bin_tree_t *)),
> > +			       reg_errcode_t fn (void *, bin_tree_t *),
> >   			       void *extra);
> 
> For corrections like that I suggest the style "reg_errcode_t (*fn) (void *, 
> bin_tree_t *)" instead, as that's the usual style in glibc and I expect it is 
> the style that was intended in regcomp.c anyway.

Thanks for the advice. I reported it on the glibc tracker:
https://sourceware.org/bugzilla/show_bug.cgi?id=26725

Bruno