float conversion / presentation problem ?

Hi folks,

i've noticed an problem with conversion from real to float -
this produces ugly values. (in fact it seems to be real->float8)

> fxignal=# SELECT 12.345::real::float;
> float8
> ------------------
> 12.3450002670288

Maybe its not really an conversion problem, but an bug in sprintf(),
(there were some other float related bugs known in glibc), as these
examples let me suspect:

> fxignal=# SELECT 12.345::real::float::real;
> float4
> --------
> 12.345

> fxignal=# SELECT ((12.345::real::float8)-(0.345::float8))::real;
> float4
> --------
> 12

I noticed this behaviour on postgresql-7.4.1 and 7.4.3 on glibc-2.3.2

BTW: real is an alias to float4 ?

regards,
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Enrico Weigelt == metux IT service

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