C programming hint

[Mark Hamilton]

> > I found a way to initialize an array of characters without using a loop.
> > Here is the method I used:
> > 
> > 	char blanks[SIZE];	/* declare array of SIZE elements */
> > 	
> > 	blanks[0] = ' ';	/* initialize 1st element */
> > 
> > 	strncpy(blanks + 1, blanks, SIZE - 1);	/* initialize entire array */
> > 		   ^^^       ^^^       ^^^
> > 		    |         |         |
> > 		destination  source   how many characters to copy 
> > 
> > The trick is to use strncpy in an almost recursive way.
> > Well, I hope you found this useful.
> 
> Unfortunately, strncpy uses the "loop" that you are trying to avoid.  It
> also makes a redundant (in this case) check for the null character each time
> through the loop that should be avoided.

One would hope that the compiler (or optimizer) would realize what's 
going on here, and do something a little more clever than looping.
Especially since this is a strncpy, so the check for the null character
isn't done.  I must admit that I am new to Unix C, but on VMS (and I
beleive TOPS20, for whoever uses that) C, the compiler will turn this
into a MOVC instruction (or a BLT on the '20).  These are both the accepted
method for filling a region.

Mark Hamilton
-- 
The opinions expessed above are -- or maybe they aren't...
	Mark Hamilton - Burroughs Advanced Systems Group
			Boulder, CO 80301
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