FreeBasic Any Keyword

Last modified October 18, 2026

The FreeBasic Any keyword has several uses: as Any Ptr for generic pointer types that can point to any data type, as an initializer (= Any) that leaves a variable or array uninitialized, and in array bounds (Dim a(Any)) to declare dynamic arrays.

Basic Definition

In FreeBasic, Any Ptr is a pointer type that can point to any data type, providing flexibility for functions that must accept different pointer types. A pure Any Ptr is not type checked by the compiler; it must be cast to a concrete pointer type (for example Integer Ptr) before it is dereferenced. The = Any initializer is used with Dim to leave a variable or array uninitialized, so it contains whatever was previously in memory.

The Any keyword is useful for creating generic functions that work with pointers to different data types, and for declaring variables and arrays that should not be automatically initialized to zero.

Any Ptr Basic Usage

This example shows how to use Any Ptr to create a generic pointer that can point to different data types.

any_basic.bas

Dim As Integer value1 = 42
Dim As Double value2 = 3.14159
Dim As String value3 = "Hello"

Dim p As Any Ptr

p = @value1
Print "Integer value: "; *Cast(Integer Ptr, p)

p = @value2
Print "Double value: "; *Cast(Double Ptr, p)

p = @value3
Print "String value: "; *Cast(String Ptr, p)

Here we declare an Any Ptr variable that can point to different data types. We assign addresses of integer, double, and string variables to the same pointer, and then use Cast to access the values through the appropriate pointer type.

Any with Arrays

The Any keyword is used with arrays to indicate that they should not be automatically initialized to zero.

any_array.bas

Dim As Integer a(0 To 9) = Any  '' uninitialized array
Dim As Double d(0 To 4)         '' initialized to zero

Print "Uninitialized array values:"
For i As Integer = 0 To 9
    Print "a("; i; ") = "; a(i)
Next

Print "Initialized array values:"
For i As Integer = 0 To 4
    Print "d("; i; ") = "; d(i)
Next

This example shows the difference between initialized and uninitialized arrays. The array declared with = Any is not guaranteed to contain zeros; it holds whatever bytes were previously in that memory, which may happen to be zero. The regular array is always initialized to zero.

Any Ptr in Function Parameters

Functions can accept Any Ptr parameters to handle pointers to different data types.

any_function.bas

Declare Sub PrintBytes(ByVal x As Any Ptr)

Dim As Integer num = 1234
Dim As Double dbl = 3.14159
Dim As String text = "Hello"

PrintBytes(@num)
PrintBytes(@dbl)
PrintBytes(@text)

Sub PrintBytes(ByVal x As Any Ptr)
    Dim As Integer i
    Print "Raw bytes: ";
    For i = 0 To 7  '' Print first 8 bytes
        Print Cast(UByte Ptr, x)[i] & " ";
    Next
    Print
End Sub

The PrintBytes subroutine accepts an Any Ptr parameter, allowing it to work with pointers to different data types. It interprets the data as raw bytes, demonstrating how Any Ptr provides low-level access.

Complete Example with Any Ptr

This comprehensive example demonstrates both uses of the Any keyword: uninitialized arrays and generic pointer parameters.

any_complete.bas

Declare Sub echo(ByVal x As Any Ptr)

Dim As Integer a(0 To 9) = Any '' uninitialized array
Dim As Double  d(0 To 4)       '' initialized to zero

Dim p As Any Ptr

Dim pa As Integer Ptr = @a(0)
Print "Not initialized ";
echo pa       '' pass to echo a pointer to integer

Dim pd As Double Ptr = @d(0)
Print "Initialized ";
echo pd       '' pass to echo a pointer to double

p = pa     '' assign to p a pointer to integer
p = pd     '' assign to p a pointer to double

Sleep

Sub echo (ByVal x As Any Ptr)
    Dim As Integer i
    For i = 0 To 39
        ' Echo interprets the data in the pointer as bytes
        Print Cast(UByte Ptr, x)[i] & " ";
    Next
    Print
End Sub

This example shows the practical use of Any in FreeBasic. The echo subroutine accepts any pointer type and interprets the data as raw bytes. The arrays show the two allocation styles: the = Any array is left uninitialized, so its bytes are not guaranteed to be zero, while the regular array is zeroed. Note that Sleep waits for a key press before the program ends.

Any Initialization Syntax

The Any keyword is also used to indicate that variables or arrays should not be initialized, leaving their contents unpredictable for performance reasons.

any_init.bas

Dim As Integer uninit = Any       '' not initialized
Dim As Integer init = 0           '' initialized to 0

Dim As Integer uninit_array(0 To 4) = Any  '' not initialized
Dim As Integer init_array(0 To 4)          '' initialized to 0

Print "Uninitialized variable: "; uninit
Print "Initialized variable: "; init

Print "Uninitialized array values:"
For i As Integer = 0 To 4
    Print "uninit_array["; i; "] = "; uninit_array(i)
Next

Print "Initialized array values:"
For i As Integer = 0 To 4
    Print "init_array["; i; "] = "; init_array(i)
Next

This example demonstrates using Any to prevent automatic initialization. Uninitialized variables and arrays contain whatever data was previously in memory, which can be useful for performance when you plan to immediately assign values.

This tutorial covered the FreeBasic Any keyword with practical examples showing its usage in scenarios where pointer flexibility and uninitialized memory allocation are useful.

Author

My name is Jan Bodnar. I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and eight e-books. I have more than ten years' experience teaching programming.

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