Changeset c4e3419c

Timestamp:

Feb 15, 2021, 1:52:46 PM (4 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

79debb02

Parents:

17d6214

Message:

formatting, update discussion on unnamed aggregates in C

File:

• doc/user/user.tex (modified) (3 diffs)

doc/user/user.tex

@@ -11 +11 @@
 %% Created On       : Wed Apr  6 14:53:29 2016
 %% Last Modified By : Peter A. Buhr
-%% Last Modified On : Mon Feb 15 09:54:33 2021
-%% Update Count     : 4442
+%% Last Modified On : Mon Feb 15 13:48:53 2021
+%% Update Count     : 4452
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
@@ -1247 +1247 @@
 \begin{cfa}
 struct Person {                                                         $\C{// aggregate}$
-        struct Name {                                                   $\C{// nesting}$
-                char first[20], last[20];
-        } name;
-        struct Address {                                                $\C{// nesting}$
-                ...
-        } address;
+        struct Name { char first[20], last[20]; } name $\C{// nesting}$
+        struct Address { ... } address                  $\C{// nesting}$
         int sex;
 };
@@ -1271 +1267 @@
 
 C allows unnamed nested aggregates that open their scope into the containing aggregate.
-However, this feature is only useful for ©union© aggregates.
+This feature is used to group fields for attributes and/or with ©union© aggregates.
 \begin{cfa}
 struct S {
+        struct { int g,  h; } __attribute__(( aligned(64) ));
+        int tag;
         union {
-                char @c@;   int @i@;   double @d@;
+                struct { char c1,  c2; } __attribute__(( aligned(128) ));
+                struct { int i1,  i2; };
+                struct { double d1,  d2; };
         };
-        int tag;
-} s;
-@s@.tag; @s@.c; @s@.i; @s@.d;                           $\C{// no nested qualification for union fields}$
+};
+s.g; s.h; s.tag; s.c1; s.c2; s.i1; s.i2; s.d1; s.d2;
 \end{cfa}