On 21 Aug 2009, at 15:07, Frank Mori Hess wrote:
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On Friday 21 August 2009, Edward Grace wrote:
boost::result_of<O()>::type
I don't have experience with boost::result_of,
Me neither... Well, if you don't count the last couple of hours.
but is it right to add parenthesis?
I don't think so, from the doc: "Given an lvalue f of type F and lvalues t1, t2, ..., tN of types T1, T2, ..., TN, respectively, the type result_of<F(T1, T2, ..., TN)
::type defines the result type of the expression f(t1, t2, ...,tN). "
Since my function/functors take no arguments I took that to mean, assuming a function 'o' corresponding to the funtion type O result_of<O()>::type should resolve to the result (return type) of doing 'o()' - the function o(). This does appear to be the case in the code I submitted, at least for the ordinary functions. If I omit the parentheses then it compares the type of O (a function pointer returning an unsigned int) and unsigned int -- not what I want. Perhaps 'result type' and 'return type' are two subtly different things in this context.
That looks to me like you are asking for the return type of a function type that takes no arguments and returns an object of type O.
I don't think so - but I'm a little stumped... -ed