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From: LLACROIX@carleton.EDU (Les LaCroix)
Newsgroups: comp.os.vms
Subject: re: LIB$INIT_TIMER
Message-ID: <8805291409.AA25532@ucbvax.Berkeley.EDU>
Date: 26 May 88 15:14:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 20

In a recent article, Peter Scott (pjs%grouch@jpl-mil.jpl.nasa.gov) writes:
> The documentation for LIB$INIT_TIMER states that it takes different actions
> base on whether the argument handle-adr is absent, zero, or non-zero.
> 
> How do you get the "absent" effect when calling from C?  I have invariably
> found that I have to specify a 0 explicitly as a parameter when calling
> system routines where if I were using FORTRAN I would leave the argument
> blank.

Note that the parameter for LIB$INIT_TIMER is passed by reference.  In
Fortran, an absent parameter is equivalent to %VAL(0).  In C:

	Absent:		lib$init_timer( 0 );	/* 0 by value */
	Zero:		lib$init_timer( &0 );	/* 0 by reference */
	Non-zero:	lib$init_timer( &x );	/* variable x by reference */

Les LaCroix
SPSS Inc., 402 Washington, Northfield MN USA 55057-2027 tel 507/663-1205
lacroix%spssnf@carleton.edu (CSnet)
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