Red Hat ENTERPRISE LINUX 4 - DEVELOPER TOOLS GUIDE, Руководство пользователя

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116 Chapter 14. Using gdb with Different Languages
.*, -
4
*
Dereferences of pointers to members.
[]
Array indexing.
a
[
i
]
is defined as
*(
a
+
i
)
. Same precedence as
-
4
.
()
Function parameter list. Same precedence as
-
4
.
::
C ++ scope resolution operator. Defined on
struct
,
union
, and
class
types.
::
Doubled colons also represent the gdb scope operator (refer to Section 10.1 Expressions ). Same
precedence as
::
, above.
If an operator is redefined in the user code, gdb usually attempts to invoke the redefined version instead
of using the operator’s predefined meaning.
14.4.1.2. C and C ++ constants
gdb allows you to express the constants of C and C ++ in the following ways:
•
Integer constants are a sequence of digits. Octal constants are specified by a leading
0
(that is, zero),
and hexadecimal constants by a leading
0x
or
0X
. Constants may also end with a letter
l
, specifying
that the constant should be treated as a
long
value.
•
Floating point constants are a sequence of digits, followed by a decimal point, followed by a
sequence of digits, and optionally followed by an exponent. An exponent is of the form:
e[[+]|-]
nnn
, where
nnn
is another sequence of digits. The
+
is optional for positive exponents.
A floating-point constant may also end with a letter
f
or
F
, specifying that the constant should be
treated as being of the
float
(as opposed to the default
double
) type; or with a letter
l
or
L
,
which specifies a
long double
constant.
•
Enumerated constants consist of enumerated identifiers, or their integral equivalents.
•
Character constants are a single character surrounded by single quotes (
’
), or a number--the ordinal
value of the corresponding character (usually its ascii value). Within quotes, the single character
may be represented by a letter or by escape sequences , which are of the form
\
nnn
, where
nnn
is
the octal representation of the character’s ordinal value; or of the form
\
x
, where
x
is a predefined
special character--for example,
\n
for newline.
•
String constants are a sequence of character constants surrounded by double quotes (
"
). Any valid
character constant (as described above) may appear. Double quotes within the string must be pre-
ceded by a backslash, so for instance
"a\"b’c"
is a string of five characters.
•
Pointer constants are an integral value. You can also write pointers to constants using the C operator
&
.
•
Array constants are comma-separated lists surrounded by braces
{
and
}
; for example,
{1,2,3}
is a
three-element array of integers,
{{1,2}, {3,4}, {5,6}}
is a three-by-two array, and
{&"hi",
&"there", &"fred"}
is a three-element array of pointers.