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Various small fixes. 

* c.texi (Lvalues): Dereferencing fn ptr is not an lvalue.
String constant is an lvalue.
Array constructor is an lvalue.
(Write Assignments Separately): Minor cleanup.
(Integer Variations): State minimum sizes of numeric types.
(Unicode Character Codes): Explain invalid universal character names.
(Structures): Define "compound type" and index it.
This commit is contained in:
Richard Stallman 2024-01-30 20:29:54 -05:00
parent db3b2f364c
commit 61fc722320
2 changed files with 37 additions and 14 deletions
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10
ChangeLog
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@ -1,3 +1,13 @@
2024-01-30 Richard Stallman <rms@gnu.org>
* c.texi (Lvalues): Dereferencing fn ptr is not an lvalue.
String constant is an lvalue.
Array constructor is an lvalue.
(Write Assignments Separately): Minor cleanup.
(Integer Variations): State minimum sizes of numeric types.
(Unicode Character Codes): Explain invalid universal character names.
(Structures): Define "compound type" and index it.
2024-01-12 Richard Stallman <rms@gnu.org>
* c.texi: fix typos.

41
c.texi
View File

@ -2646,7 +2646,7 @@ A variable.
@item
A pointer-dereference expression (@pxref{Pointer Dereference}) using
unary @samp{*}.
unary @samp{*}, if its type is not a non-function type.
@item
A structure field reference (@pxref{Structures}) using @samp{.}, if
@ -2665,7 +2665,13 @@ An array-element reference using @samp{[@r{@dots{}}]}, if the array
is an lvalue.
@item
A structure or union constructor.
A string constant (@pxref{String Constants}).
@item
An array constructor (@pxref{Constructing Array Values}).
@item
A structure or union constructor (@pxref{Structure Constructors}).
@end itemize
If an expression's outermost operation is any other operator, that
@ -2989,7 +2995,7 @@ if (x = advance (x), x != 0)
@noindent
However, putting the assignment in a separate statement is usually clearer
unless the assignment is very short, because it reduces nesting.
(unless the assignment is very short), because it reduces nesting.
@node Execution Control Expressions
@chapter Execution Control Expressions
@ -3978,10 +3984,10 @@ platform, too. Even for GNU C, there is no general rule.
In theory, all of the integer types' sizes can vary. @code{char} is
always considered one ``byte'' for C, but it is not necessarily an
8-bit byte; on some platforms it may be more than 8 bits. ISO C
specifies only that none of these types is narrower than the ones
above it in the list in @ref{Basic Integers}, and that @code{short}
has at least 16 bits.
8-bit byte; on some platforms it may be more than 8 bits. @code{short
int} and @code{int} are at least two bytes long (it may be longer).
@code{long int} is at least four bytes long, and @code{long long int}
at least eight bytes long.
It is possible that in the future GNU C will support platforms where
@code{int} is 64 bits long. In practice, however, on today's real
@ -4793,12 +4799,16 @@ And in an identifier:
int foo\u6C34bar = 0;
@end example
Codes in the range of @code{D800} through @code{DFFF} are limited to
very specialized uses, too specialized to explain here. Codes less
than @code{00A0} are invalid, except for @code{0024}, @code{0040}, and
@code{0060}; these characters are actually ASCII control characters,
and you can specify them with other escape sequences (@pxref{Character
Constants}).
Codes in the range of D800 through DFFF are invalid in universal
character names. Trying to write them using @samp{\u} causes an
error. Unicode calls them ``surrogate code points'' and uses them in
UTF-16 for purposes too specialized to explain here.
Codes less than 00A0 are likewise invalid in universal character
names, and likewise cause errors, except for 0024 (@samp{$}), 0040
(@samp{@@}), and 0060 (@samp{`}). Character codes which can't be
represented with universal character names can be specified with octal
or hexadecimal escape sequences (@pxref{Character Constants}).
@node Wide Character Constants
@section Wide Character Constants
@ -5850,10 +5860,13 @@ appropriate unsigned integer type.
@cindex structures
@findex struct
@cindex fields in structures
@cindex compound type
A @dfn{structure} is a user-defined data type that holds various
@dfn{fields} of data. Each field has a name and a data type specified
in the structure's definition.
in the structure's definition. Because a structure combines various
fields, each of its own type, we call a structure type a
@dfn{compound type}.
Here we define a structure suitable for storing a linked list of
integers. Each list item will hold one integer, plus a pointer