Re^6: NaNs are true

Correct, which is why uninitialised needs to be distinct from NaN

In C, the creation of an mpfr_t variable is done as follows:

mpfr_t x; /* declaration */
x = mpfr_init(); /* initializes x with a value of NaN */
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x cannot be used for anything until it has been initialized - and once initialized, x remains NaN until some other value gets assigned to it.
"Math::MPFR->new();" wraps those 2 steps. Maybe it should stop short of calling the mpfr_init() ... I'd have to play about with it before I could get my head around the usefulness (or otherwise) of doing so.

Cheers,
Rob

Comment on Re^6: NaNs are true Download Code

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Re^7: NaNs are true by ikegami (Patriarch) on Mar 01, 2011 at 05:12 UTC
Possibilities include Using an external state (e.g. NULL pointer to the mpfr_t for uninitialised). Setting the value to zero on creation. Setting the value to a specific NaN that's unlikely to occur by other means on creation.	[reply]