Pointer | Ptrkeyword

A variable declaration type modifier

Syntax

... As DataType {Pointer | Ptr}

Also documented as Ptr — one description covers them all.

Description

Declares a pointer variable.
The variable type can be a predefined type or a user-defined type.

Operator @ (Address Of) operator or VarPtr are used to take the address of a variable. The Operator * (Value Of) operator is used to dereference the pointer, that is, access the actual value stored in the memory location the pointer is pointing at.

Remarks

Dialect Differences

Not available in the -lang qb dialect unless referenced with the alias __Pointer or __Ptr.

Differences from QB

New to FreeBASIC

Example

' Create the pointer.

Dim p As Integer Ptr



' Create an integer value that we will point to using pointer "p"

Dim num As Integer = 98845



' Point p towards the memory address that variable "num" occupies.

p = @num



' Print the value stored in memory pointed to by pointer "p"

Print "Pointer 'p' ="; *p

Print 



' Print the actual location in memory that pointer "p" points at.

Print "Pointer 'p' points to memory location:"

Print p

Dim p As ZString Pointer

Dim text As String

text = "Hello World!"

p = StrPtr(text) + 6

Print text

Print *p



'' Output:

'' Hello World!

'' World!

Type mytype

    a As Integer = 12345

End Type



Dim As mytype mt



Dim As mytype Ptr pmt

pmt = @mt



Print (*pmt).a  '' or Print pmt->a



'' Output:

'' 12345

Reference

Documented in KeyPgPtr.html