[PATCH 4/5] include: improve errors when TEXT()/OLESTR() aren't implementable.

[Puetz Kevin A]

With WINE_UNICODE_NATIVE is set, literals can use L"".
With WINE_UNICODE_CHAR16 is set, literals can use u"".

Otherwise (TCHAR/_TCHAR/OLECHAR == WCHAR == unsigned short)
there is no suitable string literal syntax.

Rather than generating an expression of the wrong type (char16_t *),
these macros now expand to invalid syntax, i.e. prefix"..." which
will fail to compile. But prefix should appear in the error message,
and a descriptive identifier that one can easily search for in the
headers to see which definitions are available that would work.

Signed-off-by: Kevin Puetz 
---
 include/tchar.h    | 2 ++
 include/winnt.rh   | 5 ++++-
 include/wtypes.idl | 4 +++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/tchar.h b/include/tchar.h
index 519a9f1002..6c9035c219 100644
--- a/include/tchar.h
+++ b/include/tchar.h
@@ -253,6 +253,8 @@ typedef char16_t      _TCHAR;
 #define __T(x) u##x
 #else
 typedef unsigned short _TCHAR;
+/* no compiler support for TEXT() in _UNICODE mode, consider -fshort-wchar or -DWINE_UNICODE_CHAR16 */
+# define __T(string) _TEXT_no_compiler_utf16_literal##string
 #endif
 typedef _TCHAR        _TUCHAR;
 typedef _TCHAR        _TSCHAR;
diff --git a/include/winnt.rh b/include/winnt.rh
index 786a38f326..bcc780b2ab 100644
--- a/include/winnt.rh
+++ b/include/winnt.rh
@@ -28,8 +28,11 @@
 #  define __TEXT(string) string
 # elif defined(WINE_UNICODE_NATIVE)
 #  define __TEXT(string) L##string
-# else
+# elif defined(WINE_UNICODE_CHAR16)
 #  define __TEXT(string) u##string
+# else
+   /* no compiler support for TEXT() in UNICODE mode, consider -fshort-wchar or -DWINE_UNICODE_CHAR16 */
+#  define __TEXT(string) TEXT_no_compiler_utf16_literal##string
 # endif
 # define TEXT(string) __TEXT(string)
 #endif
diff --git a/include/wtypes.idl b/include/wtypes.idl
index a6682212b5..9d9b73d62d 100644
--- a/include/wtypes.idl
+++ b/include/wtypes.idl
@@ -289,8 +289,10 @@ typedef [string] const OLECHAR *LPCOLESTR;
 cpp_quote("#ifndef __WINESRC__")
 cpp_quote("# ifdef WINE_UNICODE_NATIVE")
 cpp_quote("#  define OLESTR(str) L##str")
-cpp_quote("# else")
+cpp_quote("# elif defined(WINE_UNICODE_CHAR16)")
 cpp_quote("#  define OLESTR(str) u##str")
+cpp_quote("# else")
+cpp_quote("#  define OLESTR(str) OLESTR_no_compiler_utf16_literal##str")
 cpp_quote("# endif")
 cpp_quote("#endif")

[Kevin Puetz]

Sorry, apparently git quiltimport cuts at the --- too, so the motive I 
intended 
to explain on the submission (but not the git commit message) got left out.

---

Omitting these macros entirely (as done with the _tcs* functions) may
produce poor error messages, particularly when used to define literals
in initializer contexts where functions calls are not allowed, like
TCHAR foo[] = TEXT("hello");

I also considered prototyping an unimplemented function, e.g.
const TCHAR *TEXT(...) __attribute__((error ("...")));
But that's gcc-specific, still fails in some initializer cases,
and I see no similar existing usage of __attribute__((error)) in wine,
so the minor advantage doesn't seem worth the portability issues.