Can a C function be pure? I guess it can... The trouble is you cannot proove its pure? But - why would you want to use a pure C function. The chances of any useful C library function being pure are slim - and the performance of GHC in some of the benchmarks shows that there is hardly any speed advantage (for a pure function)... Keean. Benjamin Franksen wrote:
On Monday 22 November 2004 23:22, Keean Schupke wrote:
It seems to me that as unsafePerformIO is not in the standard and only implemented on some compilers/interpreters, that you limit the portability of code by using it, and that it is best avoided. Also as any safe use of unsafePerformIO can be refactored to not use it I could certainly live without it.
With one exception: If a foreign function (e.g. from a C library) is really pure, then I see no way to tell that to the compiler other than using unsafePerformIO. IIRC, unsafePerformIO is in the standard FFI libraries.
Ben