what does it mean to zero out a struct?

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July 23rd, 2004, 03:51 PM

c0ldshadow

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what does it mean to zero out a struct?

just a random question that i figured someone might know the answer to: what does it mean to zero out a struct? examples would be great. just any help would be great.

peace, --ave

July 23rd, 2004, 04:12 PM

infamous41md

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Code:

struct foo bar;

memset(&bar, 0, sizeof(bar));

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July 23rd, 2004, 08:56 PM

gt3_dk

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Well to zero it out is to make it all NULL or zero... what infamous41md did is that he just "set up" a location in memory for it which was all cleared out. This is good because it's shorter than typing bar.x = 0; bar.y = 0; bar.... one after another... (and it also takes less time to execute...(right?)!) and also so that you don't have wrong uninitilized variables in your programs!

July 23rd, 2004, 09:37 PM

Dave Sinkula

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An all-bits-zero representation may not be correct for a floating point zero or a null pointer constant.

You may want to also consider something like either of these.

Code:

struct type object = {0}; /* zero out struct at initialization */
static const struct type zero = {0};
/* ... */
object = zero; /* zero out struct by assignment */

July 24th, 2004, 02:05 AM

Spectre5

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Why do you zero out a structure?? I have used them and I have never zeroed them out.....but my programs work fine...

what does zeroing out a structure do?

July 24th, 2004, 06:02 AM

DaWei_M

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Zeroing a structure is just a method of initializing it to known (possibly inappropriate, as User Name points out) values. It isn't necessary to overtly initialize all things, so long as they are initialized (or their value otherwise correctly set) prior to use. Since we're human, however, and tend to forget things, judicious initialization is a good idea. Initializing a pointer to NULL may not give you a usable value, but it DOES allow you to test that it's not usable, which is a gain over some indeterminate value it might have after creation.

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what does it mean to zero out a struct?

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