Throughout this subclause [rand], the effect of instantiating a template:
that has a template type parameter named Sseq is undefined unless the corresponding template argument is cv-unqualified and satisfies the requirements of seed sequence ([rand.req.seedseq]).
that has a template type parameter named URNG is undefined unless the corresponding template argument is cv-unqualified and satisfies the requirements of uniform random number generator ([rand.req.urng]).
that has a template type parameter named Engine is undefined unless the corresponding template argument is cv-unqualified and satisfies the requirements of random number engine ([rand.req.eng]).
that has a template type parameter named RealType is undefined unless the corresponding template argument is cv-unqualified and is one of float, double, or long double.
that has a template type parameter named IntType is undefined unless the corresponding template argument is cv-unqualified and is one of short, int, long, long long, unsigned short, unsigned int, unsigned long, or unsigned long long.
that has a template type parameter named UIntType is undefined unless the corresponding template argument is cv-unqualified and is one of unsigned short, unsigned int, unsigned long, or unsigned long long.
Throughout this subclause [rand], phrases of the form “x is an iterator of a specific kind” shall be interpreted as equivalent to the more formal requirement that “x is a value of a type satisfying the requirements of the specified iterator type.”