![]() Added: #PB_Round_Nearest support (+#PB_Round_Up and #PB_Round_Down) for Round() Question mark (?) in front of the label name.- Added: Streaming support for CatchSound() To find the address of a label, you put a This can beīecause you want to access the code or data stored at that label, or any other It can also be useful to find the address of labels in your code. This is where the processing of your callback procedure would be performed EndProcedure A special callback for the Windows OS allowing you to process window events SetWindowCallback( ) The address of a procedure is found in a similar wayĮxample Procedure WindowCB(WindowID.i, Message.i, wParam.i, lParam.i) (for some operations) which get called by the OS and allows the programmer to extend Some OSes allow you to specify callback or hook functions The most common reason to get the address of a procedure is when dealing String constants are also supported.Įxample *String = PeekC(*String) Will display 84, which is the value of 'T'įor advanced programmers. To get the address of literal string, you can use the at symbol in front of it. You must pass a pointer to this variable as you cannot pass structuredĮndStructure Procedure SetB(*myptr.astruct) To get the address of a variable in your code, you use the at symbol common reason for using this is when you want to pass a structured type variable *Pointer\x = 7 Change the second array element values ![]() *Pointer + SizeOf(Point) Move to the next array element *Pointer\x = 10 Change the first array element values Pointers ArithmeticĪrithmetic operations on the pointers are possible and practical by using SizeOf().Įxample Dim Array.Point(1) Array of points *Pointer.String = *Pointer points on *Text Debug *Pointer\s Display the string living at the address stored in *Pointer (i.e. ![]() *Text = *Text store the address of the string in memory String instead of the string itself: a such structure field is a pointer towards a string. Thus a structure field, that makes reference to a string, store only the memory address of the So string variables are managed by a different Pointers are also available in structures, for more information see the structures chapter.Īll variables have a permanent size in memory (2 bytes for Word, 4 bytes for a Long, etc.) exceptįor strings variables with lengths that can change. To reach big quantities of data without supplementary cost further to data duplication. Pointers allow to move, to read and to write easily in memory. *Points(0)\x = 10 Modify the variables through the pointers *Points(0) = Assign the first point variable to the first array slot *CurrentPoint \x = 20 Assign value 20 to Point2\x Debug Point1\xĮxample: Pointers and array Define Point1.Point, Point2.Point *CurrentPoint.Point = move to Point2's address *CurrentPoint \x = 10 Assign value 10 to Point1\x *CurrentPoint.Point = Pointer declaration, associated to a structure and initialized with Point1's address With this, the system grants them only an addressing with 32-bit pointers.īy assigning a structure to a pointer (for example *MyPointer.Point) it allows to access any memoryĪddress in a structured way (with the operator '\').Įxample: Pointers and variables Define Point1.Point, Point2.Point PureBasic x86 does not generate 64-bit executables. This guaranteed address integrity at the compilation time whatever the CPU address mode is. Every time a memory address needs to be stored in a variable, it should be done throughĪ pointer. It results from this that assigning a native type to a pointer (*Pointer.l, *Pointer.b. The absolute address is on a 64-bit range.Īs a consequence the type of a pointer depends of the CPU address mode, ('long' on 32-bit CPUĪnd 'quad' on 64-bit one for example), so a pointer is a variable of type pointer. On 64-bit processors it takes 64-bit (8 bytes, like a 'quad') in memory, because Pointer takes 32-bit (4 bytes, like a 'long') in memory On 32-bit processors the address space is limited to 32-bit, so a Space allowing to store an absolute address of the processor: 'ptr' is a variable (regular one) storing a value, '*ptr' is another variable of pointer type storing an address.īecause pointers receive only addresses as values, the memory size of a pointer is the Therefore '*ptr' and 'ptr' are two different variables. Note: unlike C/C++, in PureBasic the '*' is always part of the item name. Find the address of a variable, procedure or label (as shown below) Get the result from a function (as shown in the above example) There are only three valid methods to set the value of a pointer: MouseX = *MyScreen\MouseX Assuming the Screen structure contains a MouseX field
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