multiple unsequenced modifications

[Sam S. <sd...@gn...>]

Hi,

I get this:
--8<---------------cut here---------------start------------->8---
modules/rawsock/rawsock.c:893:48: warning: multiple unsequenced
  modifications to 'STACK' [-Wunsequenced]
--8<---------------cut here---------------end--------------->8---

because of

--8<---------------cut here---------------start------------->8---
  struct addrinfo hints = {addrinfo_flags(),
                           check_socket_domain(popSTACK()),
                           check_socket_type(popSTACK()),
                           get_socket_protocol(popSTACK()),
                           0,NULL,NULL,NULL};
--8<---------------cut here---------------end--------------->8---

It appears that the code _should_ DTRT in all commercial compilers and
GCC 3.4.6 or later.

https://stackoverflow.com/q/19881803/850781
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=11633
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#430

What should be done about this?

It is easy to rewrite the code (replace popSTACK() with STACK_??? and
add skipSTACK() at the end) but this would be a lie because
addrinfo_flags() modifies STACK too, so we are relying on the sequential
evaluation of all slots in the initialization no matter what.

The only honest way to avoid the issue is

--8<---------------cut here---------------start------------->8---
  struct addrinfo hints = {0,0,0,0,0,NULL,NULL,NULL};
  hints.ai_flags = addrinfo_flags();
  hints.ai_family = check_socket_domain(popSTACK());
  hints.ai_socktype = check_socket_type(popSTACK());
  hints.ai_protocol = get_socket_protocol(popSTACK());
--8<---------------cut here---------------end--------------->8---

Bruno, does it make sense?
It is worth bothering with?

Thanks

-- 
Sam Steingold (http://sds.podval.org/) on darwin Ns 10.3.1504
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