I think the problem is that the variadic function template is only considered declared after you specified its return type so that sum in decltype can never refer to the variadic function template itself. But I’m not sure whether this is a GCC bug or C++0x simply doesn’t allow this. My guess is that C++0x …
If by variadic arguments you mean the ellipses (as in void foo(…)), then those are made more or less obsolete by variadic templates rather than by initializer lists – there still could be some use cases for the ellipses when working with SFINAE to implement (for instance) type traits, or for C compatibility, but I …
To pass a named argument to a vararg parameter, use the spread operator: complicated(numbers = *intArrayOf(1, 2, 3, 4, 5))
Overall approach and usage The overal approach consists in packing the arguments into an std::tuple of references, exploiting the perfect forwarding machinery of std::forward_as_tuple(). This means that, at run-time, you should incur in very small overhead and no unnecessary copy/move operations. Also, the framework does not use recursion (apart from compile-time recursion, which is unavoidable …
It is hard to give a static type to the apply function, since its type depends on the type of the (possibly heterogeneous) list argument. There are at least two ways one way to write this function in Haskell that I can think of: Using reflection We can defer type checking of the application until …
Write a va_list version of your variadic method; + (NSError *)executeUpdateQuery:(NSString *)query, … { va_list argp; va_start(argp, query); NSError *error = [MyClassName executeUpdateQuery: query args:argp]; va_end(argp); return error; } + (NSError *)executeUpdateQuery:(NSString *)query args:(va_list)args { NSLogv(query,args); return nil; } This can then be called from Swift MyClassName.executeUpdateQuery(“query %d, %d %d”, args: getVaList([1,2,3,4])) Add an extension …
AFAIK ObjectiveC (just like C and C++) do not provide you with a syntax that allows what you directly have in mind. The usual workaround is to create two versions of a function. One that may be called directly using … and another one called by others functions passing the parameters in form of a …
Yes, float arguments to variadic function are promoted to double. The draft C99 standard section 6.5.2.2 Function calls says: […]and arguments that have type float are promoted to double. These are called the default argument promotions.[…] from the draft C++ standard section 5.2.2 Function call: […]a floating point type that is subject to the floating …
These are called Variadic functions. Wikipedia lists example code for C++. To portably implement variadic functions in the C programming language, the standard stdarg.h header file should be used. The older varargs.h header has been deprecated in favor of stdarg.h. In C++, the header file cstdarg should be used. To create a variadic function, an …
According to § 8.3.5.4 of the C++ standard (current draft): Where syntactically correct and where “…” is not part of an abstract-declarator, “, …” is synonymous with “…”. In short, in C++ … (ellipsis) is an operator in its own right and so can be used without the comma, but use of the comma is …