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11 messages in net.java.dev.jna.usersRe: [jna-users] char* versus wchar_t ...| From | Sent On | Attachments |
|---|---|---|
| Dale...@coats.com | May 13, 2008 5:17 am | |
| Timothy Wall | May 13, 2008 6:00 am | |
| Timothy Wall | May 13, 2008 6:05 am | |
| Dale...@coats.com | May 13, 2008 8:55 am | |
| Timothy Wall | May 13, 2008 9:06 am | |
| Dale...@coats.com | May 13, 2008 11:46 am |  .zip |
| Daniel Kaufmann | May 13, 2008 5:16 pm | |
| Dale...@coats.com | May 14, 2008 5:02 am | |
| Timothy Wall | May 14, 2008 6:10 am | |
| Dale...@coats.com | May 15, 2008 6:33 am | |
| Timothy Wall | May 15, 2008 12:38 pm |
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| Subject: | Re: [jna-users] char* versus wchar_t * in a Structure | Actions... |
|---|---|---|
| From: | Daniel Kaufmann (dani...@gmail.com) | |
| Date: | May 13, 2008 5:16:10 pm | |
| List: | net.java.dev.jna.users | |
Hi Daniel,
I believe this is not what Timothy was saying. I think he was saying something like this:
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 = new char[64]; }
NOTIFYICONDATA n = NOTIFYICONDATA(); n.szTip[0] = 'T'; n.szTip[1] = 'i'; n.szTip[2] = 'm';
Of course you can use System.arraycopy to copy from a different array. The important thing is that the array size is 64. Window will know the actual length of the string by looking for a NUL char (In java '\0' or just number 0) In your code you was provided a smaller array so the structure will be smaller than what it should, so if the Windows funtion tries to access there it will get garbage and might even get a segmentation fault.
Thanks, Daniel
----- Original Message ----- From: <Dale...@coats.com> To: <use...@jna.dev.java.net> Sent: Tuesday, May 13, 2008 3:46 PM Subject: [jna-users] char* versus wchar_t * in a Structure
On Tue, 13 May 2008 12:07:17 -0400 Timothy Wall wrote:
On May 13, 2008, at 11:56 AM, Dale...@coats.com wrote:
When I use a single primitive 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.
Primitive arrays are inlined. WStrings are converted to a pointer value.
It sounds like you're saying the following should be the same as what's shown above: 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','i','m'}; // <<Diff }
But that produces different results. Specifically, the OS makes a spot for the icon, but no icon shows-up.
--Dale--
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