On May 13, 2008, at 11:56 AM, Dale...@coats.com wrote:
When I use a single primative char, it works. In fact, I can
define structure like this, and get the tool tip to say 'Tim'.
public static class NOTIFYICONDATA extends Structure {
public int cbSize;
public HANDLE hWnd;
public int uID;
public int uFlags;
public int uCallbackMessage;
public HANDLE hIcon;
public char szTip = 'T';
public char szTip2 = 'i';
public char szTip3 = 'm';
}
If I didn't care how it looked, I could define 64 char primitives
and a goofy setter and be done with it. But I couldn't live
with myself if I did that.
If you just want the Structure to "print" pretty, redefine its
toString(). Otherwise, char[64] will occupy the same memory natively
as would 64 consecutive "char" fields.
No problem sizing the array beforehand and treading lightly
when working with that array.
The problem seems to revolve around some items in the structure
need to be by-value and others not. The handles work fine the
way it is, but under that scenario, unless I use a primitive
char, it's getting the pointer to the char[] or to the WString
instead the sequence of chars they contain.
Primitive arrays are inlined. WStrings are converted to a pointer
value.
Here's a "by value" example that I got WORKING, but it's only
got one field in the structure:
public static class TestStruct extends Structure {}
public static class ByValTestStruct extends TestStruct
implements Structure.ByValue{
Bzzzt. Structure.ByValue (cf Structure.ByReference) is a tagging
interface used to indicate that when used as an argument or return
value, the structure should be passed by value instead of by
reference. The default behavior is to pass or return by reference
(struct *), since passing structures or returning them by value is
less common usage in C.
But if I try that same technique with the rest of the items from the
real structure, it gives:
Unsupported structure field type class com.test.ti.W32API$HANDLE
That's a recently fixed bug (unable to use NativeMapped types in a
ByValue structure). However, I don't think you need a ByValue
structure in the first place.
11 messages in net.java.dev.jna.usersRe: [jna-users] char* versus wchar_t ...
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