[clang] dd4e8a5 - [docs] Fix some out-of-date / inaccurate text and missing formatting in the User's Manual.

[Richard Smith via cfe-commits]

Author: Richard Smith
Date: 2020-10-16T12:00:13-07:00
New Revision: dd4e8a54b2ba9cec78441ba537b94f4eaa5acd84

URL: https://github.com/llvm/llvm-project/commit/dd4e8a54b2ba9cec78441ba537b94f4eaa5acd84
DIFF: https://github.com/llvm/llvm-project/commit/dd4e8a54b2ba9cec78441ba537b94f4eaa5acd84.diff

LOG: [docs] Fix some out-of-date / inaccurate text and missing formatting in the User's Manual.

Added: 
    

Modified: 
    clang/docs/UsersManual.rst

Removed: 
    


################################################################################
diff  --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index f313ce72d8ed..473fbb6d8d04 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -2479,8 +2479,8 @@ Differences between various standard modes
 ------------------------------------------
 
 clang supports the -std option, which changes what language mode clang uses.
-The supported modes for C are c89, gnu89, c99, gnu99, c11, gnu11, c17, gnu17,
-c2x, gnu2x, and various aliases for those modes. If no -std option is
+The supported modes for C are c89, gnu89, c94, c99, gnu99, c11, gnu11, c17,
+gnu17, c2x, gnu2x, and various aliases for those modes. If no -std option is
 specified, clang defaults to gnu17 mode. Many C99 and C11 features are
 supported in earlier modes as a conforming extension, with a warning. Use
 ``-pedantic-errors`` to request an error if a feature from a later standard
@@ -2489,34 +2489,40 @@ revision is used in an earlier mode.
 Differences between all ``c*`` and ``gnu*`` modes:
 
 -  ``c*`` modes define "``__STRICT_ANSI__``".
--  Target-specific defines not prefixed by underscores, like "linux",
+-  Target-specific defines not prefixed by underscores, like ``linux``,
    are defined in ``gnu*`` modes.
--  Trigraphs default to being off in ``gnu*`` modes; they can be enabled by
-   the -trigraphs option.
--  The parser recognizes "asm" and "typeof" as keywords in ``gnu*`` modes;
-   the variants "``__asm__``" and "``__typeof__``" are recognized in all
+-  Trigraphs default to being off in ``gnu*`` modes; they can be enabled
+   by the ``-trigraphs`` option.
+-  The parser recognizes ``asm`` and ``typeof`` as keywords in ``gnu*`` modes;
+   the variants ``__asm__`` and ``__typeof__`` are recognized in all modes.
+-  The parser recognizes ``inline`` as a keyword in ``gnu*`` mode, in
+   addition to recognizing it in the ``*99`` and later modes for which it is
+   part of the ISO C standard. The variant ``__inline__`` is recognized in all
    modes.
 -  The Apple "blocks" extension is recognized by default in ``gnu*`` modes
-   on some platforms; it can be enabled in any mode with the "-fblocks"
+   on some platforms; it can be enabled in any mode with the ``-fblocks``
    option.
 -  Arrays that are VLA's according to the standard, but which can be
    constant folded by the frontend are treated as fixed size arrays.
    This occurs for things like "int X[(1, 2)];", which is technically a
    VLA. ``c*`` modes are strictly compliant and treat these as VLAs.
 
-Differences between ``*89`` and ``*99`` modes:
+Differences between ``*89`` and ``*94`` modes:
 
--  The ``*99`` modes default to implementing "inline" as specified in C99,
-   while the ``*89`` modes implement the GNU version. This can be
-   overridden for individual functions with the ``__gnu_inline__``
-   attribute.
 -  Digraphs are not recognized in c89 mode.
--  The scope of names defined inside a "for", "if", "switch", "while",
-   or "do" statement is 
diff erent. (example: "``if ((struct x {int
-   x;}*)0) {}``".)
+
+Differences between ``*94`` and ``*99`` modes:
+
+-  The ``*99`` modes default to implementing ``inline`` / ``__inline__``
+   as specified in C99, while the ``*89`` modes implement the GNU version.
+   This can be overridden for individual functions with the ``__gnu_inline__``
+   attribute.
+-  The scope of names defined inside a ``for``, ``if``, ``switch``, ``while``,
+  or ``do`` statement is 
diff erent. (example: ``if ((struct x {int x;}*)0)
+  {}``.)
 -  ``__STDC_VERSION__`` is not defined in ``*89`` modes.
--  "inline" is not recognized as a keyword in c89 mode.
--  "restrict" is not recognized as a keyword in ``*89`` modes.
+-  ``inline`` is not recognized as a keyword in ``c89`` mode.
+-  ``restrict`` is not recognized as a keyword in ``*89`` modes.
 -  Commas are allowed in integer constant expressions in ``*99`` modes.
 -  Arrays which are not lvalues are not implicitly promoted to pointers
    in ``*89`` modes.
@@ -2538,9 +2544,7 @@ clang tries to be compatible with gcc as much as possible, but some gcc
 extensions are not implemented yet:
 
 -  clang does not support decimal floating point types (``_Decimal32`` and
-   friends) or fixed-point types (``_Fract`` and friends); nobody has
-   expressed interest in these features yet, so it's hard to say when
-   they will be implemented.
+   friends) yet.
 -  clang does not support nested functions; this is a complex feature
    which is infrequently used, so it is unlikely to be implemented
    anytime soon. In C++11 it can be emulated by assigning lambda
@@ -2634,8 +2638,11 @@ C++ Language Features
 =====================
 
 clang fully implements all of standard C++98 except for exported
-templates (which were removed in C++11), and all of standard C++11
-and the current draft standard for C++1y.
+templates (which were removed in C++11), all of standard C++11,
+C++14, and C++17, and most of C++20.
+
+See the `C++ support in Clang <https://clang.llvm.org/cxx_status.html>` page
+for detailed information on C++ feature support across Clang versions.
 
 Controlling implementation limits
 ---------------------------------