64-bit Data Types Compared to 32-bit Data Types
Go Up to 64-bit Cross-Platform Application Development for Windows
The following tables summarize the differences and similarities between 64-bit OS data types and 32-bit OS data types.
Contents |
Delphi 32-bit and 64-bit Built-in Type Sizes
Integral types
On Win64, NativeInt is twice the size of the Win32 NativeInt, and NativeUInt is twice the size of the Win32 NativeUInt.
|
Signed Integer |
Unsigned Integer |
Delphi/32 |
Delphi/64 |
Comments |
|---|---|---|---|---|
|
ShortInt |
Byte |
1 byte |
||
|
SmallInt |
Word |
2 bytes |
||
|
LongInt |
LongWord |
4 bytes |
||
|
Integer |
Cardinal |
4 bytes |
||
|
Int64 |
UInt64 |
8 bytes |
||
|
NativeInt |
NativeUInt |
4 bytes |
8 bytes |
|
Pointer types
On 64-bit Windows, all pointer types are 8 bytes, twice the size on 32-bit Windows.
|
Pointer types |
Delphi/32 |
Delphi/64 |
|---|---|---|
|
Pointer |
4 bytes |
8 bytes |
|
string | ||
|
class instance | ||
|
class reference | ||
|
interface | ||
|
AnsiString | ||
|
WideString | ||
|
UnicodeString | ||
|
procedure pointer | ||
|
dynamic array | ||
|
PAnsiChar | ||
|
PWideChar | ||
|
PChar |
procedure of object
On 64-bit Windows, the alignment for a procedure of object is 16 bytes, twice the size on 32-bit Windows.
| procedure of object | 8 bytes | 16 bytes | ||
| 8 byte align | 8 byte align | Known as closure type |
Floating point types (including the Extended data type)
The Extended type has 2 bytes' worth less precision on 64-bit Windows.
For more information, see The Extended Data Type Is 2 Bytes Smaller on 64-bit Windows Systems.
|
Floating point types |
Delphi/32 |
Delphi/64 |
Comments |
|---|---|---|---|
|
Single |
4 bytes |
||
|
Double |
8 bytes |
||
|
Real |
8 bytes |
||
|
Extended |
10 bytes |
8 bytes |
TExtended80Rec has 10 bytes on Win64 |
|
Real48 |
6 bytes |
||
|
Comp |
8 bytes |
||
|
Currency |
8 bytes |
||
Other types
On Win64, file size has increased.
|
Other types |
Delphi/32 |
Delphi/64 |
Comments |
|---|---|---|---|
|
Boolean |
1 byte |
||
|
ByteBool |
1 byte |
||
|
WordBool |
2 bytes |
||
|
LongBool |
4 bytes |
||
|
AnsiChar |
1 byte |
||
|
WideChar |
2 bytes |
||
|
Char |
2 bytes |
||
|
ShortString |
256 bytes |
||
|
string[N] |
N+1 bytes |
||
|
Variant/OleVariant |
16 bytes |
24 bytes | |
|
File |
592 bytes |
616 bytes |
|
|
Text/TextFile |
730 bytes |
754 bytes |
720 bytes in XE release |
Constants
|
Constants |
Delphi/32 |
Delphi/64 |
|---|---|---|
|
MaxInt |
$7fffffff | |
|
MaxLongInt |
$7fffffff | |