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Can we have a function pointer which points to a function which use a varying argument list? For example, lets say i need to select a function among a number of functions based on some input T 'input'. Can i use a STL map somthing like this??
template<typename T>
map<T, T (*)(T, ...)> func_map;
If this is possible can you tell me doing so will be right thing to do with design perspective.
[Edit] Actually i have a set of algorithmic functions and i have a message field. I need to select this algorithmic function based on few bytes values on this msg. I was thinking to use hash_map with a key value w.r.t. the pointer to that algorithmic function. i wanted to be very fast as per performance, what can be bast way to implement this.
Also, the reason why i am not selecting simple if-else or switch block for this is because the value which tell us the function that need to execute can refer to some other function at later point.
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Every actual argument list must be known at compile time. In that sense it is not truly a variable argument list.
Pass-by-pointer means to pass a pointer argument in the calling function to the corresponding formal parameter of the called function. The called function can modify the value of the variable to which the pointer argument points. When you use pass-by-pointer, a copy of the pointer is passed to the function.
A function pointer is a variable that stores the address of a function that can later be called through that function pointer. This is useful because functions encapsulate behavior.
In mathematics and in computer programming, a variadic function is a function of indefinite arity, i.e., one which accepts a variable number of arguments.
Yes, it is possible to do this, but you probably shouldn't. There are a number of problems with variadic functions, including:
I would recommend you find another approach. If you give more specifics on why you need to do this, perhaps someone can give you a better option.
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