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Some folks might think: “you still use RCS”?!? And we will say, hey, at least we switched from SCCS to RCS back in … I think it was around 1994 ... at least we are keeping up! :-) :-) :-) Logs say that SCCS version 18 became RCS version 19 on 1994 March 18. RCS served us well. But now it is time to move on. And so we are switching to git. Calc releases produce a lot of file changes. In the 125 releases of calc since 1996, when I started managing calc releases, there have been 15473 file mods!
106 lines
3.2 KiB
Plaintext
106 lines
3.2 KiB
Plaintext
NAME
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* - dereference or indirection operator
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SYNOPSIS
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* X
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TYPES
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X address or lvalue
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return any
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DESCRIPTION
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When used as a binary operator, '*' performs multiplication. When
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used as a operator, '*' returns the value at a given address.
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If X is an address, *X returns the value at that address. This value
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will be an octet, lvalue, string, or number, depending on the
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type of address. Thus, for any addressable A, *&A is the same as A.
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If X is an lvalue, *X returns the current value at the address
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considered to be specified by X. This value may be an lvalue or
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octet, in which cases, for most operations except when X is the
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destination of an assignment, *X will contribute the same as X to
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the result of the operation. For example, if A and B are lvalues
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whose current values are numbers, A + B, *A + B, A + *B and *A + *B
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will all return the same result. However if C is an lvalue and A is
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the result of the assignment A = &C, then A = B will assign the value
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of B to A, *A = B will assign the value of B to C without affecting
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the value of A.
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If X is an lvalue whose current value is a structure (matrix, object,
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list, or association), the value returned by *X is a copy of the
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structure rather than the structure identified by X. For example,
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suppose B has been created by
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; mat B[3] = {1,2,3}
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then
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; A = *B = {4,5,6}
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will assign the values 4,5,6 to the elements of a copy of B, which
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will then become the value of A, so that the values of A and B will
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be different. On the other hand,
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; A = B = {4,5,6}
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will result in A and B having the same value.
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If X is an octet, *X returns the value of that octet as a number.
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The * operator may be iterated with suitable sequences of pointer-valued
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lvalues. For example, after
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; global a, b, c;
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; b = &a;
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; c = &b;
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**c returns the lvalue a; ***c returns the value of a.
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EXAMPLE
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; mat A[3] = {1,2,3}
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; p = &A[0]
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; print *p, *(p + 1), *(p + 2)
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1 2 3
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; *(p + 1) = 4
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; print A[1]
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4
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; A[0] = &a
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; a = 7
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; print **p
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7
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LIMITS
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none
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LINK LIBRARY
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none
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SEE ALSO
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address, isptr
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## Copyright (C) 1999-2006 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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##
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## Under source code control: 1997/09/06 20:03:34
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## File existed as early as: 1997
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##
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## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
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## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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