Eric Blake wrote: > According to Bruno Haible on 4/11/2008 4:43 AM: > | 1) for float to decimal conversion, think of snprintf (NULL, "%Le", x) > | or snprintf (NULL, "%Lf", x) > | > | At least in the first case, I don't see how the number of output bytes could > | be determined without doing the actual conversion. > > True, but in the first case, the maximum number of significant digits is > known in advance, so you can still use a fixed-size stack-allocated buffer > to do the work.
It also depends on the exponent. And with 'long double's you can have up to 32-bit exponents. In order to determine how 9.9999999999999999999999999999999999999999999e+3000000 rounds you need memory of size 3000000*log(10)/(8*log(2)). The only way to allocate such an amount of memory inside snprintf is through malloc. Bruno
