Please find below the mappings table for most commonly used data types along with some comments.
Native Type
(C/C++) |
JNIWrapper Type |
Comments |
|
Boolean Types
|
|
|
| bool |
Bool(1 byte), IntBool(4 bytes) |
|
|
Character Types
|
|
|
| char |
Char |
|
| wchar_t |
WideChar |
|
| uchar * |
Char, UInt8 |
|
|
Integer Types
|
|
|
| short |
ShortInt |
The unsigned types are represented by prepending U to the type name, e.g. unsigned int (or unsigned) type is UInt.
There are also types for predefined-width integers: Int8, Int16, Int32 and Int64, they also have the unsigned variants. |
| int |
Int |
|
| long |
LongInt |
|
|
Floating-point Types
|
|
|
| float |
SingleFloat |
|
| double |
DoubleFloat |
|
| long double |
LongDouble |
Long double is the same as double (8-byte floating-point value) on win32 platform. |
|
Pointer Types (not arrays)
|
|
|
| void * |
Pointer.Void |
|
| const |
Pointer.Const |
Use Pointer.Const if the referenced object is not to be modified by the calling function. |
| type * |
Pointer |
To create a pointer to the value (variable) of a known type, use the Pointer class.
For example: int *i; is Pointer i = new Pointer(new Int()); |
| type * |
Pointer.OutOnly |
Use Pointer.OutOnly if the referenced value is not read by the calling function. |
| char * |
AnsiString |
|
| wchar_t * |
WideString |
|
|
Arrays
|
|
|
| <c primitive type>[n] |
PrimitiveArray(<corresponding JNIWrapper type>.class, n); |
For example:
int i[10];
is
PrimitiveArray i =
new PrimitiveArray(Int.class, 10); |
|
Structures and Unions
|
|
|
| struct |
Structure |
|
| union |
Union |
|
|
Function Pointers
|
|
|
To create an object callable from the native code use the Callback class.
To call a function returned from the native code use the method asFunction of the Pointer.Void class. |
|
|
Windows API includes many data types that are not listed here (for example, DWORD, HANDLE). If you need to use one of such types, read Windows-specific documentation such as MSDN to find out the actual C type that corresponds to it (for example, LPSTR corresponds to char*) and use the relevant JNIWrapper type for the argument. You can also check the Windows Data Types table that we have created for your reference. |
|
