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Important: The information in this document is Not Recommended and should not be used for new development.

Current information on this Reference Library topic can be found here:

Workaround for Asynchronous SCSIAction Crashes

Q: In Mac OS X 10.1.x, why does my CFM application crash when attempting to use the asynchrounous SCSIAction calls?

A: Because of a bug (r. 2649048), the proper Mach-O to CFM glue is not being created which will cause your application to crash when SCSIAction attempts to call your CFM callback function. To workaround this problem, simply implement the code shown below instead of calling NewSCSICallbackUPP and DisposeSCSICallbackUPP. Remember to check the Tech Notes released with System Updates and major OS releases so you can remove this workaround after the underlying bug is fixed. 



SCSICallbackUPP
MyNewSCSICallbackUPP(SCSICallbackProcPtr cfmfp)
{

#if TARGET_RT_MAC_CFM


    long systemVersion = 0;


    if (Gestalt(gestaltSystemVersion, &systemVersion) == noErr && systemVersion >= 0x1010)
    {
        UInt32 temp[6] = {0x3D800000, 0x618C0000, 0x800C0000,
                          0x804C0004, 0x7C0903A6, 0x4E800420};

        // Must later dispose of allocated memory
        UInt32 * mfp = (UInt32*) NewPtr(sizeof(temp));
        mfp[0] = temp[0] | ((UInt32)cfmfp >> 16);
        mfp[1] = temp[1] | ((UInt32)cfmfp & 0xFFFF);
        mfp[2] = temp[2];
        mfp[3] = temp[3];
        mfp[4] = temp[4];
        mfp[5] = temp[5];

        MakeDataExecutable(mfp, sizeof(temp));

        return ((SCSICallbackUPP)mfp);
    }
    else
    {
        return (NewSCSICallbackUPP(cfmfp));
    }

#else

    return (NewSCSICallbackUPP(cfmfp));

#endif

}



void
MyDisposeSCSICallbackUPP(SCSICallbackUPP fp)
{

#if TARGET_RT_MAC_CFM

    long systemVersion = 0;

    if (Gestalt(gestaltSystemVersion, &systemVersion) == noErr && systemVersion >= 0x1010)
    {
        DisposePtr((char *)fp);
    }
    else
    {
        DisposeSCSICallbackUPP(fp);
    }

#else

    DisposeSCSICallbackUPP(fp);

#endif

}

Listing 1. Code to create Mach-O to CFM glue.



[Mar 18 2002]