osd@hou2d.UUCP (Orlando Sotomayor-Diaz) (05/11/86)
From: Orlando Sotomayor-Diaz (The Moderator) <cbosgd!std-c>
mod.std.c Digest Sat, 10 May 86 Volume 16 : Issue 4
Today's Topics:
Differences from April 1985 to February 1986 Draft Standard, Part 3
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Date: Sun, 27 Apr 86 01:17:06 est
From: <ihnp4!utcsri!lsuc!msb%utcsri>
Subject: Differences from April 1985 to February 1986 Draft Standard, Part 3
To: cbosgd!std-c%utcsri
# C.1 Lexical elements The program fragment x+++++y is parsed as
x ++ ++ + y, which {is a syntax error --> violates a constraint
on increment operators}, even though the parse x ++ + ++ y might
yield a correct expression.
* Forward references: expressions (#C.3) {-->, postfix increment
and decrement operators (#C.3.2.4)}.
Remark: A number of things have been reclassified from syntax to
constraints in this fashion.
# C.1.2 Identifiers
* An identifier denotes ... one of the following ... a {type -->
typedef} name ...
# C.1.2.1 Scopes of identifiers
N--> (A "function prototype" is a declaration of a function that de-
N--> clares the types of its parameters.)
# C.1.2.2 Linkages of identifiers
In the set of source files and
libraries that constitutes an entire program, every instance of a
particular identifier with "external linkage" denotes the same
function or object. If the declarations in two source files {-->
or in disjoint scopes within one source file} differ, the
behavior is undefined.
# C.1.2.2 Linkages of identifiers
For an identifier of a function or object declared with file
* scope, if its lexically first declaration {--> with file scope}
in the source file contains the keyword static, the identifier
has internal linkage.
# C.1.2.4 Storage durations of objects [An] instance of an object
that has "automatic storage duration" ... is discarded when exe-
cution of the block ends by reaching the terminating "}", by
jumping to an enclosing block, or by executing a {--> break or}
return statement.
# C.1.2.5 Types An object declared as a character (char) is large
enough to store any member of the {execution character set that
can be specified as a single-character character constant without
using an octal or hexadecimal escape sequence --> required source
character set enumerated in #B.2.1}.
# C.1.2.5 Types
There are four types of signed integers, called signed char,
short int, int, and long int. A "plain" int has the natural size
* suggested by the architecture of the execution environment {-->
(large enough to contain any value in the range INT_MIN to
INT_MAX as defined in the header <limits.h>)}; the other types
are provided to meet special needs. The set of values of each
signed integral type is a subset of the values of the next type
* in the list above. Even if the implementation defines {-->
signed char,} short int, int, or long int to have the same set of
values, they are nevertheless different types.
# C.1.2.5 Types
N--> The set of non-negative values of a signed type is a subset of
N--> its corresponding unsigned type.
# C.1.3 Constants
<--O If the value of a constant cannot be represented in the storage
<--O appropriate for that type in the execution environment, the
<--O behavior is undefined.
N--> The value of a constant shall be representable in the storage ap-
N--> propriate for its type in the execution environment.
# C.1.3.2 Integer constants
Remark: The notation [opt] below represents a subscript opt,
which means optional.
<--O integer-suffix:
<--O integer-suffix-letter
<--O integer-suffix-letter integer-suffix-letter
<--O integer-suffix-letter: one of
<--O u l U L
N--> integer-suffix:
N--> unsigned-suffix long-suffix[opt]
N--> long-suffix unsigned-suffix[opt]
N--> unsigned-suffix: one of
N--> u U
N--> long-suffix: one of
N--> l L
# C.1.3.2 Integer constants The type of an integer constant is
the first of the corresponding list in which its value can be
represented. Unsuffixed decimal: int, long int {-->, unsigned
long int}. ...
# C.1.3.4 Character constants Even if eight bits are used for ob-
jects that have type char, the construction {'\xFF1' --> '\x123'}
specifies a character constant containing only one character.
(The value of this {--> single-character} constant is
implementation-defined.) To specify a character constant contain-
ing the two characters {0xFF and 1 --> 0x12 and 3} , the con-
struction {'\x0FF1' --> '\x0123'} may be used. (The value of
this {--> two-character} constant is also implementation-
defined.)
# C.1.4 String literals A string literal has static storage dura-
tion and type "array of {const -->} char" ...
N--> If the program attempts to modify a string literal, the behavior
N--> is undefined.
# C.1.5 Operators operator: one of
...
, {--> # ##}
N--> ... The operators # and ## may occur in macro-defining prepro-
N--> cessor directives only.
# C.1.6 Punctuators punctuator: one of
[ ] ( ) { } * , : = ; ... # {## -->}
N--> The punctuator # may occur in preprocessor directives only.
# C.2.1.1 Characters and integers
* A char, or a short int {-->, or an int bit-field}, or their
signed or unsigned varieties, may be used in an expression wher-
ever an int may be used. In all cases the value is converted to
an int if an int can represent all values of the original type;
otherwise it is converted to an unsigned int. These are called
* the "integral {widening conversions --> promotions}".
Remark: The new term "promotion" is used throughout the document.
* When an integer is {converted --> demoted} to a shorter unsigned
* integer {--> or unsigned int bit-field} or unsigned char, the
result is the remainder modulo the largest unsigned number that
* can be represented plus one. When an integer is {converted -->
* demoted} to a shorter signed integer {--> or int bit-field} or
signed char, if the value cannot be represented the result is
implementation-defined.
------------------------------
End of mod.std.c Digest - Sat, 10 May 86 19:00:12 EDT
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