Re: MinGW compilation errors with Gnulib wchar.h and wctype.h

[Eli Zaretskii]

> Cc: address@hidden
> From: Paul Eggert <address@hidden>
> Date: Sun, 9 Oct 2016 11:07:46 -0700
> 
> Eli Zaretskii wrote:
> > But because string.h was included, __STRING_H_SOURCED__ is defined,
> > and MinGW's wchar.h doesn't define mbstate_t.  Gnulib's wchar.h
> 
> I suggest adding a __STRING_H_SOURCED__ check to Gnulib's lib/wchar.in.h's 
> complicated test for the special invocation convention.

Thanks for the guidance.  Indeed, the two patches below fix both
issues for me.  Please consider this for inclusion in Gnulib.


2016-10-08  Eli Zaretskii  <address@hidden>

        Fix wchar.h and wctype.h for MinGW 3.22.2

        * lib/wchar.in.h [__MINGW32__]: Add one more condition for
          special invocation, to fix issues with MinGW 3.22.2 wchar.h
          when included from <string.h>.

        * lib/wctype.in.h [__MINGW32__]: Add special invocation
          convention for MinGW 3.22.2, to solve issues with their
          wctype.h when included from <ctype.h>.

--- lib/wchar.in.h~0    2016-08-01 18:50:20.000000000 +0300
+++ lib/wchar.in.h      2016-10-10 15:44:45.178750000 +0300
@@ -35,6 +35,7 @@
      || (defined __hpux                                                 \
          && ((defined _INTTYPES_INCLUDED && !defined strtoimax)         \
              || defined _GL_JUST_INCLUDE_SYSTEM_WCHAR_H))               \
+     || (defined __MINGW32__ && defined __STRING_H_SOURCED__)           \
      || defined _GL_ALREADY_INCLUDING_WCHAR_H)
 /* Special invocation convention:
    - Inside glibc and uClibc header files, but not MinGW.
@@ -44,6 +45,8 @@
      and once directly.  In both situations 'wint_t' is not yet defined,
      therefore we cannot provide the function overrides; instead include only
      the system's <wchar.h>.
+   - With MinGW 3.22, when <string.h> includes <wchar.h>, only some part of
+     <wchar.h> is actually processed, and that doesn't include 'mbstate_t'.
    - On IRIX 6.5, similarly, we have an include <wchar.h> -> <wctype.h>, and
      the latter includes <wchar.h>.  But here, we have no way to detect whether
      <wctype.h> is completely included or is still being included.  */


--- lib/wctype.in.h~0   2016-08-01 18:50:20.000000000 +0300
+++ lib/wctype.in.h     2016-10-10 15:55:32.350625000 +0300
@@ -25,13 +25,25 @@
  * wctrans_t, and wctype_t are not yet implemented.
  */
 
-#ifndef address@hidden@_WCTYPE_H
-
 #if __GNUC__ >= 3
 @PRAGMA_SYSTEM_HEADER@
 #endif
 @PRAGMA_COLUMNS@
 
+#if (defined __MINGW32__ && defined __CTYPE_H_SOURCED__)
+
+/* Special invocation convention:
+   - With MinGW 3.22, when <ctype.h> includes <wctype.h>, only some part of
+     <wctype.h> is being processed, which doesn't include the idempotency
+     guard.   */
+
address@hidden@ @NEXT_WCTYPE_H@
+
+#else
+/* Normal invocation convention.  */
+
+#ifndef address@hidden@_WCTYPE_H
+
 #if @HAVE_WINT_T@
 /* Solaris 2.5 has a bug: <wchar.h> must be included before <wctype.h>.
    Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
@@ -512,3 +524,4 @@
 
 #endif /* address@hidden@_WCTYPE_H */
 #endif /* address@hidden@_WCTYPE_H */
+#endif