Binvalues

[Bela Berde]

Hi,

struct BinValues

{

int intVal;

double doubleVal;

}

is Ok, but

struct TripleValues

{

std::string strVal;

int intVal;

double doubleVal;

}

is not Ok; Why?

Thanks

[Robert Escriva]

This isn't part of the LevelDB API, which deals in slices.

I assume you are taking these structs and doing something like:

TripleValues t(...)
leveldb::Slice value(&t, sizeof(t));

This will work for BinValues because it's a struct of plain old data
(you'll see this called a POD struct). The TripleValues struct won't
work because strVal is a non-plain type, and what you'd be serializing
is the members of the struct. In this case, that would be pointers to
the actual string data that you want to store.

You'll need to transform TripleValues into a byte string that does what
you want.

-Robert

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[Florian Weimer]

* Robert Escriva:

> This isn't part of the LevelDB API, which deals in slices.
>
> I assume you are taking these structs and doing something like:
>
> TripleValues t(...)
> leveldb::Slice value(&t, sizeof(t));
>
> This will work for BinValues because it's a struct of plain old data
> (you'll see this called a POD struct).

The padding (a 4-byte hole between the int and double members) could
still break some things, I think.