Re: [PATCH] socklen: do not depend on sys_socket

[Bruno Haible]

Hi Paul,

> * m4/socklen.m4 (gl_PREREQ_TYPE_SOCKLEN_T): New macro, taken from
> parts of gl_PREREQ_SYS_H_SOCKET.
> (gl_TYPE_SOCKLEN_T): Require it instead of requiring
> gl_PREREQ_SYS_H_SOCKET.  Check for ws2tcpip.h only if
> sys_socket is also used.
> * m4/sys_socket_h.m4 (gl_PREREQ_SYS_H_SOCKET): Require
> gl_PREREQ_TYPE_SOCKLEN_T instead of doing its work ourselves.
> ...
> * modules/socklen: Do not depend on sys_socket.

There are two problems with this patch:

1) "Check for ws2tcpip.h only if sys_socket is also used." This is wrong
   for Emacs: emacs/nt/inc/sys/socket.h does include <ws2tcpip.h>. So this
   patch would cause socklen_t to be defined in config.h at configure time,
   but then when Emacs code includes <sys/socket.h> which includes
   <ws2tcpip.h> the declaration
     typedef int socklen_t;
   expands to
     typedef int int;
   which will lead to a compilation error.

2) If modules/socklen does not depend on sys_socket, undoing the patch of
   <http://lists.gnu.org/archive/html/bug-gnulib/2006-01/msg00168.html>,
   then the 'Include' statement of the socklen module should be changed from

     <sys/types.h>
     <sys/socket.h>

   to

     #include <sys/types.h>
     #if HAVE_SYS_SOCKET_H
     #include <sys/socket.h>
     #endif

   otherwise a non-Emacs package that asks for 'socklen' but not for
   'sys_socket' would get a compilation error. Also a test that defines
   HAVE_SYS_SOCKET_H needs to be added, then.

Bruno
-- 
In memoriam Fred Scamaroni <http://fr.wikipedia.org/wiki/Fred_Scamaroni>