Compare methods

[ch4]

I have these two methods in order to set the bits of a memory block to zero.

First

char newHeader[BF_BLOCK_SIZE];

//....
      //Set up new header
      memset(newHeader,0,BF_BLOCK_SIZE);

//...

Second

char newHeader[BF_BLOCK_SIZE];

//...
     //Set up new header
     for(i=0;i<BF_BLOCK_SIZE;i++)
          newHeader[i]=0;

//...

Trying both i see no difference.
Is there something that diversify those two methods or it's just the same way ?

[Maz]

depending on the underlying library implementation, one may be more efficient than the other. I would assume that memset might be more efficient in some cases.

(since it may be utilizing wider buses by writing more than one char at once)

[matsp]

It would depend a lot on the number of elements, and optimization settings of the compiler, as well as what processor is being used, to name a few factors.

For nearly all cases except where the size is tiny, the memset call will be faster. If in doubt, measure it. [But unless it's really time-critical, who cares?]

--
Mats

[ch4]

Thank you !

[itCbitC]

The only thing not going for memset() is the overhead of an extern function call.

[brewbuck]

The only thing not going for memset() is the overhead of an extern function call.

Any decent compiler will have an intrinsic implementation of memset() -- it should not result in a function call, at least if optimization is enabled.

[itCbitC]

Any decent compiler will have an intrinsic implementation of memset() -- it should not result in a function call, at least if optimization is enabled.

If that's the case then it's a win-win for memset().