Array length : size_t

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D's Array length is currently of type size_t, which means on 32 
bit it's an uint and on 64 bit an ulong. This is difficult: What 
if I want to give the length of an array as parameter to some C 
functions which accepts only an int?
What is the right/safe way to do this? A cast? Or is there 
something better?
I like to avoid cast's if they aren't necessary.