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Re: Value size ? [message #42907 is a reply to message #42904]

Mon, 14 April 2014 06:00

mirek
Messages: 13980
Registered: November 2005

Ultimate Member

mingodad wrote on Sun, 13 April 2014 21:43

I saw in several places talking about efficiency but when I look at sizeof(Value) == 48 (64bits) I'm not sure about it.

sizeof(Value) is 16 bytes. I guess you have tried in DEBUG, where there is some additional diagnostics data.

Quote:

I saw that Value has a String member called "data" and also an Atomic member called "refcount" to be used in special cases, but String also has the same "refcount" for special cases, isn't it a repetition ?

Not at all.

Quote:

I was looking at sizeof(boost::any) == 8 (64bits) and sizeof(cdiggins::any) == 16 (64bits)

How much _total_ memory would boost::any consume if you assign it an int or "Hello world"?

Value will still use 16 bytes _total_ in both cases.

BTW, to investigate such issues further, there is benchamarks/sizeof which I use to track this. Also funny is benchamrks/idmapBench, which benchmarks (among others) ValueMap against STL (that is, high-level U++ thing against low-level STL thing).

Mirek

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