Clear

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Clear

Sets a number of bytes, starting at a variable, to zero or to a given value.

Syntax

Declare Sub Clear cdecl ( ByRef dst As Any, ByVal value As Long = 0, ByVal bytes As UInteger )

Parameters

• dst
• value
• bytes

Description

Clear sets one or more bytes in memory to a certain value (the default value is zero (0) if not specified). The starting address is taken from a reference to a variable or array element.

NOTE: In order to clear memory referenced by a Pointer, it must be dereferenced first (or else specifying in argument term the ByVal keyword in front of the pointer name). Otherwise, Clear will try to clear the bytes at the pointer variable's memory location.

Remarks

Usage

Clear( dst, [value], bytes )

Differences from QB

• The behavior and usage is new to FreeBASIC The keyword CLEAR was used in QB to erase all variables, close all files, and optionally change the stack size. This use is not supported in FreeBASIC.

See also

• Erase
• Reset

Examples

'create an array with 100 elements

Dim array(0 To 99) As Integer

'clear the contents of the array to 0, starting with the first element

Clear array(0), , 100 * SizeOf(Integer)

'allocate 20 bytes of memory

Dim As Byte Ptr p = Allocate(20)

'set each of the first ten bytes to 0

Clear *p, 0, 10

'set each of the next ten bytes to 42

Clear p[10], 42, 10

'check the values of the allocated bytes

For i As Integer = 0 To 19

    Print i, p[i]

Next

'deallocate memory

Deallocate p

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Category: Memory Functions
Kind: sub

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Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.