variadic-functions

There are related questions, such as How can I pass in 2 parameters to a AsyncTask class? , but I ran into the difficulty of trying in vain to pass multiple primitives as parameters to an AsyncTask, so I want to share what I discovered. This subtlety is not captured in the existing questions and answers, so I want to help out anyone who runs into the same problem as I did and save them the pain. The question is this: I have multiple primitive parameters (e.g. two longs) that I want to pass to an AsyncTask to be executed in the background--how can it be done? (My answer...after struggling with

Simple question, how make this code working ? public class T { public static void main(String[] args) throws Exception { new T().m(); } public // as mentioned by Bozho void foo(String... s) { System.err.println(s[0]); } void m() throws Exception { String[] a = new String[]{"hello", "kitty"}; System.err.println(a.getClass()); Method m = getClass().getMethod("foo", a.getClass()); m.invoke(this, (Object[]) a); } } Output: class [Ljava.lang.String; Exception in thread "main" java.lang.IllegalArgumentException: wrong number of arguments at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Anyone have a reference for the representation of va_list in the x86_64 ABI (the one used on Linux)? I'm trying to debug some code where the stack or arguments seem corrupt and it would really help to understand what I'm supposed to be seeing... Skurmedel I made my comment into an answer. This may help . It's a reference, albeit lightweight ( EDIT : original link dead; replaced Wayback Machine-preserved link). The Variable Argument List reference starts on page 50, then it goes on, page 52-53 documents va_list : The va_list Type The va_list type is an array containing a single element of one

Is it possible to declare a method that will allow a variable number of parameters ? What is the symbolism used in the definition that indicate that the method should allow a variable number of parameters? Answer: varargs BalusC That's correct. You can find more about it in the Oracle guide on varargs . Here's an example: void foo(String... args) { for (String arg : args) { System.out.println(arg); } } which can be called as foo("foo"); // Single arg. foo("foo", "bar"); // Multiple args. foo("foo", "bar", "lol"); // Don't matter how many! foo(new String[] { "foo", "bar" }); // Arrays are also

From a previous question : If you attempt to pass a float to printf , it'll be promoted to double before printf receives it printf() is a variadic function right? So does a variadic function promote a float argument to a double before passing it? 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