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NAME
* - dereference or indirection operator
SYNOPSIS
* X
TYPES
X address or lvalue
return any
DESCRIPTION
When used as a binary operator, '*' performs multiplication. When
used as a operator, '*' returns the value at a given address.
If X is an address, *X returns the value at that address. This value
will be an octet, lvalue, string, or number, depending on the
type of address. Thus, for any addressable A, *&A is the same as A.
If X is an lvalue, *X returns the current value at the address
considered to be specified by X. This value may be an lvalue or
octet, in which cases, for most operations except when X is the
destination of an assignment, *X will contribute the same as X to
the result of the operation. For example, if A and B are lvalues
whose current values are numbers, A + B, *A + B, A + *B and *A + *B
will all return the same result. However if C is an lvalue and A is
the result of the assignment A = &C, then A = B will assign the value
of B to A, *A = B will assign the value of B to C without affecting
the value of A.
If X is an lvalue whose current value is a structure (matrix, object,
list, or association), the value returned by *X is a copy of the
structure rather than the structure identified by X. For example,
suppose B has been created by
; mat B[3] = {1,2,3}
then
; A = *B = {4,5,6}
will assign the values 4,5,6 to the elements of a copy of B, which
will then become the value of A, so that the values of A and B will
be different. On the other hand,
; A = B = {4,5,6}
will result in A and B having the same value.
If X is an octet, *X returns the value of that octet as a number.
The * operator may be iterated with suitable sequences of pointer-valued
lvalues. For example, after
; global a, b, c;
; b = &a;
; c = &b;
**c returns the lvalue a; ***c returns the value of a.
EXAMPLE
; mat A[3] = {1,2,3}
; p = &A[0]
; print *p, *(p + 1), *(p + 2)
1 2 3
; *(p + 1) = 4
; print A[1]
4
; A[0] = &a
; a = 7
; print **p
7
LIMITS
none
LINK LIBRARY
none
SEE ALSO
address, isptr
## Copyright (C) 1999-2006 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1997/09/06 20:03:34
## File existed as early as: 1997
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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