Re: modules poll* fail on mingw-w64 for i686 and x86_64

[Bruno Haible <bruno@clisp.org>]

Hannes Müller wrote:
> In file included from poll.c:39:
> C:/Users/hm/Documents/msys32/mingw32/i686-w64-
> mingw32/include/winsock2.h:1155:16: error: redefinition of 'struct
> pollfd'
>  1155 | typedef struct pollfd {
>       |                ^~~~~~
> In file included from poll.c:32:
> ./poll.h:506:8: note: originally defined here
>   506 | struct pollfd
>       |        ^~~~~~

Thanks for the report. I reproduce it, when adding -D_WIN32_WINNT=0x0600
(-> compilation for Windows Vista or newer) to the CPPFLAGS.

This patch fixes it.


2019-06-30  Bruno Haible  <bruno@clisp.org>

	poll-h: Fix compilation error on mingw with _WIN32_WINNT >= 0x0600.
	Reported by Hannes Müller <h.c.f.mueller@gmx.de>.
	* lib/poll.in.h: Include <winsock2.h>.
	(POLL*, pollfd): Override on native Windows.
	* m4/poll_h.m4 (gl_POLL_H): Invoke gl_PREREQ_SYS_H_WINSOCK2.
	* modules/poll-h (Files): Add m4/sys_socket_h.m4.
	(Makefile.am): Substitute HAVE_WINSOCK2_H.

diff --git a/lib/poll.in.h b/lib/poll.in.h
index 5cf6566..0b115dc 100644
--- a/lib/poll.in.h
+++ b/lib/poll.in.h
@@ -33,6 +33,13 @@
 #ifndef _@GUARD_PREFIX@_POLL_H
 #define _@GUARD_PREFIX@_POLL_H
 
+/* On native Windows, get the 'struct pollfd' type and the POLL* macro
+   definitions before we override them.  mingw defines them in <winsock2.h>
+   if _WIN32_WINNT >= 0x0600.  */
+#if @HAVE_WINSOCK2_H@
+# include <winsock2.h>
+#endif
+
 
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
@@ -41,6 +48,21 @@
 
 #if !@HAVE_POLL_H@
 
+# if @HAVE_WINSOCK2_H@
+/* Override the definitions from <winsock2.h>.  */
+#  undef POLLIN
+#  undef POLLPRI
+#  undef POLLOUT
+#  undef POLLERR
+#  undef POLLHUP
+#  undef POLLNVAL
+#  undef POLLRDNORM
+#  undef POLLRDBAND
+#  undef POLLWRNORM
+#  undef POLLWRBAND
+#  define pollfd rpl_pollfd
+# endif
+
 /* fake a poll(2) environment */
 # define POLLIN      0x0001      /* any readable data available   */
 # define POLLPRI     0x0002      /* OOB/Urgent readable data      */
diff --git a/m4/poll_h.m4 b/m4/poll_h.m4
index 94de19b..8f0e105 100644
--- a/m4/poll_h.m4
+++ b/m4/poll_h.m4
@@ -1,4 +1,4 @@
-# poll_h.m4 serial 2
+# poll_h.m4 serial 3
 dnl Copyright (C) 2010-2019 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -23,6 +23,8 @@ AC_DEFUN([gl_POLL_H],
   dnl <poll.h> is always overridden, because of GNULIB_POSIXCHECK.
   gl_CHECK_NEXT_HEADERS([poll.h])
 
+  gl_PREREQ_SYS_H_WINSOCK2 dnl for HAVE_WINSOCK2_H
+
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[#include <poll.h>]],
diff --git a/modules/poll-h b/modules/poll-h
index c1d3969..3c68758 100644
--- a/modules/poll-h
+++ b/modules/poll-h
@@ -4,6 +4,7 @@ A POSIX-like <poll.h>.
 Files:
 lib/poll.in.h
 m4/poll_h.m4
+m4/sys_socket_h.m4
 
 Depends-on:
 extensions
@@ -29,6 +30,7 @@ poll.h: poll.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(WARN_ON_USE_H)
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_POLL_H''@|$(NEXT_POLL_H)|g' \
 	      -e 's/@''GNULIB_POLL''@/$(GNULIB_POLL)/g' \
+	      -e 's|@''HAVE_WINSOCK2_H''@|$(HAVE_WINSOCK2_H)|g' \
 	      -e 's|@''HAVE_POLL''@|$(HAVE_POLL)|g' \
 	      -e 's|@''REPLACE_POLL''@|$(REPLACE_POLL)|g' \
 	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \