Reallocate
Reallocates storage for an existing reserved block of memory
pointer
The address of the reallocated memory. A null (0) pointer is returned if reallocation was unsuccessful, and the original memory pointed to by pointer remains unchanged.
Attempts to reallocate, or resize, memory previously allocated with Allocate. The contents of the buffer are preserved, although if count is less than the original size of the memory block, the buffer will be truncated.
If pointer is null (0), then ReAllocate behaves identically to Allocate.
Reallocated memory must be deallocated, or freed, with Deallocate when no longer needed.
This function is not part of the FreeBASIC runtime library, it is an alias for the C runtime library's realloc, so it's not guaranteed to be thread safe in all platforms.
NOTE: Reallocating a pointer inside an object function, when that pointer contains the parent object of the function, is undefined, and will likely result in horrible crashes.
Syntax
Usage
result = Reallocate( pointer, count )
Parameters
pointer
The address of allocated memory to be reallocated.
countThe number of bytes, in total, to be reallocated.
Return Value
The address of the reallocated memory. A null (0) pointer is returned if reallocation was unsuccessful, and the original memory pointed to by pointer remains unchanged.
Description
Attempts to reallocate, or resize, memory previously allocated with Allocate. The contents of the buffer are preserved, although if count is less than the original size of the memory block, the buffer will be truncated.
If pointer is null (0), then ReAllocate behaves identically to Allocate.
Reallocated memory must be deallocated, or freed, with Deallocate when no longer needed.
This function is not part of the FreeBASIC runtime library, it is an alias for the C runtime library's realloc, so it's not guaranteed to be thread safe in all platforms.
NOTE: Reallocating a pointer inside an object function, when that pointer contains the parent object of the function, is undefined, and will likely result in horrible crashes.
Example
Dim a As Integer Ptr, b As Integer Ptr, i As Integer
a = Allocate( 5 * SizeOf(Integer) ) ' Allocate memory for 5 integers
If a = 0 Then Print "Error Allocating a": End
For i = 0 To 4
a[i] = (i + 1) * 2 ' Assign integers to the buffer
Next i
b = Reallocate( a, 10 * SizeOf(Integer) ) ' Reallocate memory for 5 additional integers
If b <> 0 Then
a = b
For i = 5 To 9
a[i] = (i + 1) * 2 ' Assign more integers to the buffer
Next i
For i = 0 To 9 ' Print the integers
Print i, a[i]
Next i
Print
Else '' Reallocate failed, memory unchanged
Print "Error Reallocating a"
For i = 0 To 4 ' Print the integers
Print i, a[i]
Next i
Print
End If
Deallocate a ' Clean up
a = Allocate( 5 * SizeOf(Integer) ) ' Allocate memory for 5 integers
If a = 0 Then Print "Error Allocating a": End
For i = 0 To 4
a[i] = (i + 1) * 2 ' Assign integers to the buffer
Next i
b = Reallocate( a, 10 * SizeOf(Integer) ) ' Reallocate memory for 5 additional integers
If b <> 0 Then
a = b
For i = 5 To 9
a[i] = (i + 1) * 2 ' Assign more integers to the buffer
Next i
For i = 0 To 9 ' Print the integers
Print i, a[i]
Next i
Else '' Reallocate failed, memory unchanged
Print "Error Reallocating a"
For i = 0 To 4 ' Print the integers
Print i, a[i]
Next i
End If
Deallocate a ' Clean up
Dialect Differences
- Not available in the -lang qb dialect unless referenced with the alias __Reallocate.
Differences from QB
- New to FreeBASIC
See also
