Re: C++ and read redefinition

[Bruno Haible]

> 2020-12-25  Bruno Haible  <bruno@clisp.org>
> 
>       Make it possible to turn off each of the Windows oldnames workarounds.

And likewise for 'mkdir'.


2020-12-25  Bruno Haible  <bruno@clisp.org>

        Make it possible to turn off the mkdir override on Windows.
        * lib/sys_stat.in.h (mkdir): Conditionalize through GNULIB_MKDIR and
        GNULIB_MDA_MKDIR. Also support GNULIB_POSIXCHECK.
        * m4/sys_stat_h.m4 (gl_SYS_STAT_H_DEFAULTS): Initialize GNULIB_MKDIR,
        GNULIB_MDA_MKDIR.
        * modules/sys_stat (Makefile.am): Substitute GNULIB_MKDIR,
        GNULIB_MDA_MKDIR.
        * modules/mkdir (configure.ac): Invoke gl_SYS_STAT_MODULE_INDICATOR.
        * doc/posix-functions/mkdir.texi: Mention also the 'sys_stat' module.

diff --git a/doc/posix-functions/mkdir.texi b/doc/posix-functions/mkdir.texi
index 141d35d..1162947 100644
--- a/doc/posix-functions/mkdir.texi
+++ b/doc/posix-functions/mkdir.texi
@@ -4,21 +4,15 @@
 
 POSIX specification:@* 
@url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/mkdir.html}
 
-Gnulib module: mkdir
+Gnulib module: sys_stat or mkdir
 
-Portability problems fixed by Gnulib:
+Portability problems fixed by either Gnulib module @code{sys_stat} or 
@code{mkdir}:
 @itemize
 @item
 This function is declared in different header files (namely, @code{<io.h>} or
 @code{<direct.h>}) on some platforms:
 mingw, MSVC 14.
 @item
-When the argument ends in a slash, the function call fails on some platforms.
-@item
-This function mistakenly succeeds on @samp{mkdir("d/./",mode)} on
-some platforms:
-Cygwin 1.5.x, mingw, MSVC 14.
-@item
 On Windows platforms (excluding Cygwin), this function is called @code{_mkdir}
 and takes only one argument.  The fix (without Gnulib) is to define a macro
 like this:
@@ -31,6 +25,16 @@ or
 @end smallexample
 @end itemize
 
+Portability problems fixed by Gnulib module @code{mkdir}:
+@itemize
+@item
+When the argument ends in a slash, the function call fails on some platforms.
+@item
+This function mistakenly succeeds on @samp{mkdir("d/./",mode)} on
+some platforms:
+Cygwin 1.5.x, mingw, MSVC 14.
+@end itemize
+
 Portability problems not fixed by Gnulib:
 @itemize
 @end itemize
diff --git a/lib/sys_stat.in.h b/lib/sys_stat.in.h
index 4b4ec65..faca522 100644
--- a/lib/sys_stat.in.h
+++ b/lib/sys_stat.in.h
@@ -608,21 +608,20 @@ _GL_WARN_ON_USE (lstat, "lstat is unportable - "
 #endif
 
 
-#if @REPLACE_MKDIR@
-# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
-#  undef mkdir
-#  define mkdir rpl_mkdir
-# endif
+#if @GNULIB_MKDIR@
+# if @REPLACE_MKDIR@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mkdir
+#   define mkdir rpl_mkdir
+#  endif
 _GL_FUNCDECL_RPL (mkdir, int, (char const *name, mode_t mode)
-                              _GL_ARG_NONNULL ((1)));
+                               _GL_ARG_NONNULL ((1)));
 _GL_CXXALIAS_RPL (mkdir, int, (char const *name, mode_t mode));
-#else
+# elif defined _WIN32 && !defined __CYGWIN__
 /* mingw's _mkdir() function has 1 argument, but we pass 2 arguments.
    Additionally, it declares _mkdir (and depending on compile flags, an
    alias mkdir), only in the nonstandard includes <direct.h> and <io.h>,
    which are included above.  */
-# if defined _WIN32 && ! defined __CYGWIN__
-
 #  if !GNULIB_defined_rpl_mkdir
 static int
 rpl_mkdir (char const *name, mode_t mode)
@@ -631,16 +630,44 @@ rpl_mkdir (char const *name, mode_t mode)
 }
 #   define GNULIB_defined_rpl_mkdir 1
 #  endif
-
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mkdir
 #   define mkdir rpl_mkdir
 #  endif
 _GL_CXXALIAS_RPL (mkdir, int, (char const *name, mode_t mode));
 # else
 _GL_CXXALIAS_SYS (mkdir, int, (char const *name, mode_t mode));
 # endif
-#endif
 _GL_CXXALIASWARN (mkdir);
+#elif defined GNULIB_POSIXCHECK
+# undef mkdir
+# if HAVE_RAW_DECL_MKDIR
+_GL_WARN_ON_USE (mkdir, "mkdir does not always support two parameters - "
+                 "use gnulib module mkdir for portability");
+# endif
+#elif @GNULIB_MDA_MKDIR@
+/* On native Windows, map 'mkdir' to '_mkdir', so that -loldnames is not
+   required.  In C++ with GNULIB_NAMESPACE, avoid differences between
+   platforms by defining GNULIB_NAMESPACE::mkdir always.  */
+# if defined _WIN32 && !defined __CYGWIN__
+#  if !GNULIB_defined_rpl_mkdir
+static int
+rpl_mkdir (char const *name, mode_t mode)
+{
+  return _mkdir (name);
+}
+#   define GNULIB_defined_rpl_mkdir 1
+#  endif
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mkdir
+#   define mkdir rpl_mkdir
+#  endif
+_GL_CXXALIAS_RPL (mkdir, int, (char const *name, mode_t mode));
+# else
+_GL_CXXALIAS_SYS (mkdir, int, (char const *name, mode_t mode));
+# endif
+_GL_CXXALIASWARN (mkdir);
+#endif
 
 
 #if @GNULIB_MKDIRAT@
diff --git a/m4/sys_stat_h.m4 b/m4/sys_stat_h.m4
index a1cb988..14b72db 100644
--- a/m4/sys_stat_h.m4
+++ b/m4/sys_stat_h.m4
@@ -1,4 +1,4 @@
-# sys_stat_h.m4 serial 35   -*- Autoconf -*-
+# sys_stat_h.m4 serial 36   -*- Autoconf -*-
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -71,6 +71,7 @@ AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
   GNULIB_GETUMASK=0;    AC_SUBST([GNULIB_GETUMASK])
   GNULIB_LCHMOD=0;      AC_SUBST([GNULIB_LCHMOD])
   GNULIB_LSTAT=0;       AC_SUBST([GNULIB_LSTAT])
+  GNULIB_MKDIR=0;       AC_SUBST([GNULIB_MKDIR])
   GNULIB_MKDIRAT=0;     AC_SUBST([GNULIB_MKDIRAT])
   GNULIB_MKFIFO=0;      AC_SUBST([GNULIB_MKFIFO])
   GNULIB_MKFIFOAT=0;    AC_SUBST([GNULIB_MKFIFOAT])
@@ -81,6 +82,7 @@ AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
   GNULIB_OVERRIDES_STRUCT_STAT=0; AC_SUBST([GNULIB_OVERRIDES_STRUCT_STAT])
   dnl Support Microsoft deprecated alias function names by default.
   GNULIB_MDA_CHMOD=1;   AC_SUBST([GNULIB_MDA_CHMOD])
+  GNULIB_MDA_MKDIR=1;   AC_SUBST([GNULIB_MDA_MKDIR])
   GNULIB_MDA_UMASK=1;   AC_SUBST([GNULIB_MDA_UMASK])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_FCHMODAT=1;      AC_SUBST([HAVE_FCHMODAT])
diff --git a/modules/mkdir b/modules/mkdir
index 2f1850c..fb24458 100644
--- a/modules/mkdir
+++ b/modules/mkdir
@@ -15,6 +15,7 @@ gl_FUNC_MKDIR
 if test $REPLACE_MKDIR = 1; then
   AC_LIBOBJ([mkdir])
 fi
+gl_SYS_STAT_MODULE_INDICATOR([mkdir])
 
 Makefile.am:
 
diff --git a/modules/sys_stat b/modules/sys_stat
index 6bf6b29..8a9adb5 100644
--- a/modules/sys_stat
+++ b/modules/sys_stat
@@ -42,6 +42,7 @@ sys/stat.h: sys_stat.in.h $(top_builddir)/config.status 
$(CXXDEFS_H) $(ARG_NONNU
              -e 's/@''GNULIB_GETUMASK''@/$(GNULIB_GETUMASK)/g' \
              -e 's/@''GNULIB_LCHMOD''@/$(GNULIB_LCHMOD)/g' \
              -e 's/@''GNULIB_LSTAT''@/$(GNULIB_LSTAT)/g' \
+             -e 's/@''GNULIB_MKDIR''@/$(GNULIB_MKDIR)/g' \
              -e 's/@''GNULIB_MKDIRAT''@/$(GNULIB_MKDIRAT)/g' \
              -e 's/@''GNULIB_MKFIFO''@/$(GNULIB_MKFIFO)/g' \
              -e 's/@''GNULIB_MKFIFOAT''@/$(GNULIB_MKFIFOAT)/g' \
@@ -51,6 +52,7 @@ sys/stat.h: sys_stat.in.h $(top_builddir)/config.status 
$(CXXDEFS_H) $(ARG_NONNU
              -e 's/@''GNULIB_UTIMENSAT''@/$(GNULIB_UTIMENSAT)/g' \
              -e 
's/@''GNULIB_OVERRIDES_STRUCT_STAT''@/$(GNULIB_OVERRIDES_STRUCT_STAT)/g' \
              -e 's/@''GNULIB_MDA_CHMOD''@/$(GNULIB_MDA_CHMOD)/g' \
+             -e 's/@''GNULIB_MDA_MKDIR''@/$(GNULIB_MDA_MKDIR)/g' \
              -e 's/@''GNULIB_MDA_UMASK''@/$(GNULIB_MDA_UMASK)/g' \
              -e 's|@''HAVE_FCHMODAT''@|$(HAVE_FCHMODAT)|g' \
              -e 's|@''HAVE_FSTATAT''@|$(HAVE_FSTATAT)|g' \