====== Functions ======

Functions in **XC=BASIC** are procedures that return a value of a certain type.

**XC=BASIC** supports:

  * Several built-in functions
  * The [[USR|USR() function]] to call a machine language function
  * [[fun|User-defined functions]] (since version 2.2)


===== Calling overloaded functions =====

Some of the built-in functions are overloaded and thus they may return values of miscellaneous types. When calling a function, you must explicitly specify which type you wish to call by appending the right [[https://en.wikipedia.org/wiki/Sigil_(computer_programming)|sigil]] to the function name. For example, the [[ABS|ABS function]] can return an integer or a float:

  myInt = abs(-5)
  myFloat%= abs%(-3.14)

Another example is [[RND|RND]] that can return three different types:

  myRandomByte!  = rnd!()
  myRandomInt    = rnd()
  myRandomFloat% = rnd%()
  
Note: user defined functions may not be overloaded.
===== Defining user functions =====  

Please refer to the [[fun|FUN ... ENDFUN]] directive for details.