A silly question regarding function types

A silly question regarding function types

[Gary Oblock]

Note, isn't a problem, rather, it's something that puzzles me.

On walking a function types argument types this way

for ( arg = TYPE_ARG_TYPES ( func_type);
       arg != NULL;
       arg = TREE_CHAIN ( arg))
    {
       .
       .
     }

I noticed an extra void argument that didn't exist
tagged on the end.

I then noticed other code doing this (which I copied:)

for ( arg = TYPE_ARG_TYPES ( func_type);
        arg != NULL && arg != void_list_node;
        arg = TREE_CHAIN ( arg))
     {
         .
         .
      }

What is going on here???

Thanks,

Gary



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Re: A silly question regarding function types

[Richard Biener]

On Fri, Sep 4, 2020 at 4:39 AM Gary Oblock via Gcc <gcc@gcc.gnu.org> wrote:
>
> Note, isn't a problem, rather, it's something that puzzles me.
>
> On walking a function types argument types this way
>
> for ( arg = TYPE_ARG_TYPES ( func_type);
>        arg != NULL;
>        arg = TREE_CHAIN ( arg))
>     {
>        .
>        .
>      }
>
> I noticed an extra void argument that didn't exist
> tagged on the end.
>
> I then noticed other code doing this (which I copied:)
>
> for ( arg = TYPE_ARG_TYPES ( func_type);
>         arg != NULL && arg != void_list_node;
>         arg = TREE_CHAIN ( arg))
>      {
>          .
>          .
>       }
>
> What is going on here???

Without a void_list_node on the end it's a variadic function

> Thanks,
>
> Gary
>
>
>
> CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and contains information that is confidential and proprietary to Ampere Computing or its subsidiaries. It is to be used solely for the purpose of furthering the parties' business relationship. Any unauthorized review, copying, or distribution of this email (or any attachments thereto) is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto.