speedbar.gadget and 16bit IDs

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kas1e

Posted on: 2025/5/25 14:07 #1

Home away from home

Discovered something interesting today:
In all my previous Amiga-specific coding (main loop, message handling, switch-case on gadget IDs), I’ve always used int32 code, and it worked fine for everything — until now.

While experimenting with speedbar.gadget, I noticed that code wasn’t matching any of my expected IDs. Instead of getting 1, 2, 3, 4, 5, 6 ., I got:


unknown button ID: 65536

unknown button ID: 131072

unknown button ID: 196608

unknown button ID: 262144

unknown button ID: 32760

unknown button ID: 393216

Turns out that SpeedBar.gadget encodes the button ID in the upper 16 bits of "int32 code", while WMHI_GADGETMASK (0xFFFF) filters the lower 16 bits of result. So unless you shift code >> 16, switch will never match.

For quick fix i manually shift the ID out of code:


if ((result & WMHI_GADGETMASK) == GID_SPEEDBAR)

{

    uint32 buttonID = code >> 16;

    switch (buttonID)

    {

        case SBID_NEW:   // etc.

        .....

But what i am wondering about now: should I always keep code value as int32 and just shift when needed (seems rare, and speedbar.gadget only specific), or should I make "code" as uint16 from the start to avoid this kind of surprise and hope int16 will bring no other issues instead ?:)

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jabirulo

Re: speedbar.gadget and 16bit IDs

Posted on: 2025/5/25 20:27 #2

Just can't stay away

Hi, WM_HANDLEINPUT ('code' variable)? IIRC it should be uint16:


ULONG HandleMainWindowIDCMP(const BOOL AllowIconify)

{

 ULONG result,done=FALSE;

 uint16 code;

 Upload=FALSE;



 while (MainWin_Object &&

    (result=IDoMethod(MainWin_Object, WM_HANDLEINPUT, &code))!=WMHI_LASTMSG)

 {

  switch (result & WMHI_CLASSMASK)

  {

   case WMHI_CLOSEWINDOW:

    done=TRUE;

    break;

   case WMHI_GADGETUP:

    switch (result & WMHI_GADGETMASK)

        {

     case MG_SpeedBar:

            if (!HandleSpeedBar(code)) done=TRUE;

        break;

...

then look in https://github.com/OS4Welt/AmiFTP/blob/master/src/amiftp/SpeedBar.c
above snipped is from amiftp too (https://github.com/OS4Welt/AmiFTP/blob ... /amiftp/MainWindow.c#L115)

https://wiki.amigaos.net/amiga/autodocs/window_cl.doc.txt

AOS4.1/SAM460ex/PPC460EX-1155MHZ/2048MB/RadeonRX550/HDD/DVDRW

salass00

Re: speedbar.gadget and 16bit IDs

Posted on: 2025/5/25 20:52 #3

Just can't stay away

@kas1e

That's because you are defining code wrong. It should be a 16-bit variable (e.g. uint16/int16) not an int32.

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