Clear
Syntax
Usage
Clear( dst, [value], bytes )
Parameters
dst
starting address of some memory
valuethe value to set all bytes equal to
bytesnumber of bytes to clear
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. Otherwise, Clear will try to clear the bytes at the pointer variable's memory location.
Example
'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(1), , 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
Dim array(0 To 99) As Integer
'clear the contents of the array to 0, starting with the first element
Clear array(1), , 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
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
