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Technote 1017

MARCH 1996

All developers writing software for the Mac OS who wish to take advantage of the new features and enhancements offered by the System 7.5 Update 2.0 should refer to this document for both information about these new features and references to other sources of information describing some of these new features in greater detail.

System Software 7.5.3 offers a number of performance enhancements that positively affect many applications, as well as a number of bug fixes that provide more stable operation under varying circumstance. Most of the enhancements are transparent to applications , and developers won't have to make any changes in already existing software to take advantage of them; developers wanting to incorporate some of the new features offered by the system into their upcoming software, however, will find information regarding these facilities herein.

Contents

System 7.5 Update 2.0 and System 7.5.3 Two Implementations If System Software 7.5.3 is Present... Features Present in Update 2.0 New Features and Changes Alias Manager Apple Guide Apple Menu Options Apple PhotoCD Access AppleShare Workstation Client Software Communications Toolbox Control Manager Dialog Manager Digital Signature Facilities (DigiSign) Display Manager DMA Serial Driver (SerialDMA) Dynamic Recompilation (DR) Emulator File System Finder Changes Fixed Point Math Font Manager

Hardware Cursor Support InterfaceLib Changes MathLib Changes Memory Manager Menu Manager Monitors Control Panel Open Transport Power Off Key Disabler PowerTalk Printing Process Manager QuickDraw QuickTime 2.1 Resource Manager SCSI Driver Changes Sound Manager 3.2 Standard File Package Thread Manager Translucent Dragging of PixMaps Video Driver Changes WorldScript Power Adapter

System 7.5 Update 2.0 and System 7.5.3

Those machines shipping with System 7.5.3 pre-installed may not have all the bug fixes of System 7.5 Update 2.0. The differences are listed in the section Features Present in Update 2.0.

If System Software 7.5.3 is Present...

If System Software 7.5.3 is present, then the Gestalt selector gestaltSystemVersion ('sysv') will return a version number of 0x00000753 in the response parameter as illustrated in Figure 1.

As discussed in the previous section, there are two different versions of the System 7.5.3 software--one version that comes installed on a new machine, and another version established by applying Update 2.0 to a machine configured with System 7.5, 7.5.1, or 7.5.2. To distinguish between these two versions of the system software, the 'sysu' Gestalt selector has been provided. It will return the version number of the currently installed system update. The version number returned is formatted according to the same conventions as the version numbering used in 'vers' resources, as illustrated in Figure 2.

The presence of the 'sysu' Gestalt selector allows application programs to determine if the current installed system software version was established using the system update. The 'sysu' Gestalt selector will only be defined if a system update package was used to establish the current system version--the 'sysu' selector is not defined on machines shipped with System 7.5.3 installed.

For example, here is how you can use the 'sysv' and the 'sysu' Gestalt selectors to establish information about System 7.5.3:

long response, updateversion;
	OSErr err;
	Boolean seven_five_three;
	Boolean is_an_update;
	
	seven_five_three = false;
	is_an_update = false;
	
	err = Gestalt(gestaltSystemVersion, &response);
	if (err == noErr) {
		seven_five_three = (response == 0x00000753);
		if (seven_five_three) {
			err = Gestalt('sysu', &updateversion);
			is_an_update = (err == noErr);
		}
	}
	/* at this point, seven_five_three will be true if system 7.5.3
	is the current operating system, and is_an_update will be true
	if the current system version was established by update. if
	is_an_update is true, updateversion will contain the System
	update's version number (0x02008000 for system 7.5 update 2.0). */

• The Network Software Selector (NSS) found in Update 2.0 provides a choice between using classic networking and Open Transport. When classic networking is selected, the NSS will hide the OT libraries in the Extensions folder so that native OT applications do not bind to the libraries when the rest of OT is inactive. On machines shipping with 7.5.3 installed, Open Transport is the only networking option and the NSS is not available.

• Update 2.0 corrects a memory leak found in the Standard File Package included in the System 7.5.3 software that ships installed on some machines. Here, 512 bytes were left allocated in the application heap zone each time Standard File was used to open a file.

• Update 2.0 includes a newer version of IRTalk.

• The LocalTalk driver (DRVR 9) included with the classic networking software in Update 2.0 is a newer version of the driver that includes corrections to some problems reported on PowerBooks.

• The SCSI Manager provided in System 7.5 Update 2.0 corrects problems found in the 7.5.3 SCSI Manager when it has been installed on either a PowerBook Duo 210 or a PowerBook Duo 230.

• The implementation of the Process Manager has been modified to increase the size of the application heap zone to accommodate the new version of MathLib which is loaded into the application heap zone in System 7.5 Update 2.0. On machines shipped with 7.5.3 installed, the application heap size is not increased as MathLib not loaded into the application heap zone.

• Update 2.0 includes a correction in the Power Manager software such that a very low PowerBook battery level can no longer be misinterpreted as indicating a full battery.

• Update 2.0 does not load the A/ROSE extension on machines where it is not needed.

• Update 2.0 corrects a problem appearing in 68K PowerBook Duos where they could hang when waking from sleep state while docked with virtual memory turned on.

• Update 2.0 corrects a problem found in PowerBooks where PC cards were left unlocked after waking from sleep, leading to possible data loss.

• Update 2.0 corrects a problem where the Native SCSI Manager could cause a page fault while loading if virtual memory was on when running on 6100/7100/8100 class machines.

• In Update 2.0, the Power Manager library's data section is allocated globally rather than on a per-instance basis as it is in the 7.5.3 software that ships installed on some machines. Allocating the data section globally prevents a crash when the user turns AppleTalk on as a side effect of opening the AppleTalk or TCP/IP control panels. PowerBook users may have encountered this problem.

• Update 2.0 corrects a crashing bug found in the boot-time progress bar that would occur at startup time under low memory conditions. Machines shipping with System 7.5.3 installed also ship with sufficient memory installed to ensure that this problem will not occur.

• Update 2.0 corrects a problem in the Display Manager where long menus were not being drawn to the correct screen height after the screen size was reconfigured.

• Display Manager included in Update 2.0 has been modified so that it does not attempt to write its preferences information to disk at an inappropriate time (which could have lead to display problems after system startup).

• Update 2.0 corrects a problem in the Notification Manager where an incorrect icon would be displayed in the Application menu after a> alert, displayed with an icon, was dismissed.
• The Notification Manager no longer causes a redraw of the menu bar clock and menu bar battery level indicators when an alert sound is played.

• Update 2.0 corrects a problem in the SetPwrKey() routine which would trash two bytes on the stack when the routine returned an error code other than noErr.

• The default recording mode is set to two's complement on PCI-based computer platforms running Update 2.0, making the default recording settings on these machines equivalent to the default recording settings on other Mac OS-based computers. The default recording mode is one's complement on PCI-based computer platforms shipping with System 7.5.3 installed.

• Update 2.0 ships with a newer version of Drive Setup (version 1.0.4) that corrects some potential problems on hard disks being set up for disconnect/reconnect incorrectly.

• The Native SCSI Manager corrects a problem where the computer would hang if an array or tape drive was being used with SCSI ID 5. This problem would only occur if two SCSI devices (one with the ID 5), connected to the same bus, were utilizing the bus at the same time. This problem did not cause any data corruption, and is present in both the Native SCSI Manager found in System 7.5.3 and System 7.5 Update 2.0.

• Update 2.0 includes a custom install option for a system addition that corrects a problem where third-party network client software would hang at either restart or shutdown.

• Update 2.0 ships with a newer version of AppleGuide (version 2.0.2) that corrects a problem related to some of the crashes users have experienced with Microsoft Office. Microsoft also has several bug fixes available for unrelated Office crashes.

• Update 2.0 ships with a newer version of Apple Menu Options (version 1.1.2) that corrects problems reported in international software.

See Also:

• The "Version Resource" section on page 7-69 of Inside Macintosh: Macintosh Toolbox Essentials.
• The "Interpreting Gestalt Responses" section on page 1-10 of Inside Macintosh: Operating System Utilities.

Enhancements

The Alias Manager has been unified into one common source code base for all Mac OS-based computer platforms. Previously, there were three different variants of the Alias Manager that may have been installed: the basic version, the PowerTalk version, and the ARA version. Now, the facilities offered by each of these have been unified into one common implementation, guaranteeing consistent Alias Manager behavior across all of the Mac OS platform.

Support has been added to enhance the Alias Manager's user interface in the dialogs presented when attempting to mount a remote AppleShare server using an alias. The Alias Manager dialogs now allow for user authentication within these dialogs, improving the convenience of this facility.

Bug Fixes

Apple Guide

Enhancements

Apple Guide now allows more than 8 mixin files to be open at one time. The limit to the number of guide files that may be open simultaneously is determined by available memory.

Apple Guide is now fully native.

Option-click on a Guide Sequence panel copies the contents of the panel to the Clipboard.

Apple Guide now plays sounds asynchronously.

Bug Fixes

Difficulties displaying coach marks in modal dialogs have been eliminated.

A memory leak in Apple Guide's heap occurring whenever a new data base was opened has been stopped.

A problem where every 21st index item would erroneously disappear under certain circumstances has been corrected. Most commonly this error would appear when multiple mixin files were in use.

Apple Guide 2.0 defaults to US ASCII sorting only if the current script is Roman and the current language is English.

International resources are now handled correctly.

Warning:

Developers should be aware that AppleGuide uses the file type 'HELP' for its files. Applications programs should avoid using this type for their own data files so that Macintosh Easy Open does not incorrectly call their applications to open guide files.

Enhancements

AMO's GetResource patch is now only installed when the Apple menu is selected and drawn on the screen. This eliminates any possible conflicts with the Toolbox call GetResource while other applications are running, and reduces the call overhead for GetResource while the Apple Menu is not being held down.

AMO was originally written as a modular INIT making extensive use of calls and patches routed through its own private jump tables. Architectural changes in AMO moving away from this model have both reduced AMO's memory footprint and improved performance by reducing AMO's processing requirements.

Bug Fixes

A problem where submenus were not being drawn or drawn too large under certain conditions was fixed.

Apple PhotoCD Access

Enhancements

AppleShare Workstation Client Software

Enhancements

The new version also briefly caches some information from the desktop database for selected AFP requests such as GetForkParms and GetFileDirParms to avoid unnecessary disk access. In this case, the cache is small and is flushed often to avoid stale information.

Communications Toolbox

Bug Fixes

Control Manager

Bug Fixes

Dialog Manager

Bug Fixes

Digital Signature Facilities (DigiSign)

Enhancements

The Digital Signature facility also has been updated to accommodate the order in which resource types are returned by the new native Resource Manager routine Get1IndType when calculating digital signatures for files containing multiple resource types. The new Digital Signature Manager will compensate for signatures created using the older resource ordering, correctly verifying signatures created on machines running with the 68K-based Resource Manager.

Warning:

It is recommended that all users of PowerTalk's digital signature facilities upgrade their installed software to include the new version of the Digital Signature Manager.

See Also:

• The "Digital Signature Manager" chapter of Inside Macintosh: AOCE Application Interfaces
• The Resource Manager section in this Technote.

Enhancements

The Display Manager 2.0 power state calls (DMGetAVPowerState and DMSetAVPowerState) control power states for displays without using direct calls to video drivers.

The routine DMSaveScreenPrefs saves the current display configuration to disk.

Display Manager callbacks registered with a process serial number are made within the application's context (A5, patches, resource file chains, etc.).

Bug Fixes

See Also:

• The Display Manager documentation on the Reference Library Developer CD.

Enhancements & Bug Fixes

• Centris 660AV
• Quadra 660AV
• Quadra 840AV
• Power Macintosh 6100/60
• Power Macintosh 6100/66
• Power Macintosh 7100/66
• Power Macintosh 7100/80
• Power Macintosh 8100/80
• Power Macintosh 8100/100
• Power Macintosh 8100/110.

Other machines that support the new DMA Serial Driver include Performa models and Apple Workgroup Server models derived from the machines listed above.

Note:

The new DMA Serial Driver is only applicable in Macintosh models where there are DMA channels servicing a standard Z8530 Serial Communications Controller. The new driver is also known as "SerialDMA 2.0."

SerialDMA has been implemented in native code for PowerPC-based machines.

The new serial driver will return a version number of 9 for the version query Status call (csCode = 9). Applications wishing to take advantage of the new features offered by the SerialDMA 2.0 driver should check for this version number.

Application developers wishing to take advantage of new features offered by the SerialDMA 2.0 driver should refer to Technote 1018 - "Understanding the DMA Serial Driver."

Important:

The new serial driver will return a version number of 9 for the version query Status call (csCode = 9). It is not guaranteed that the new features offered by this version of the Serial Driver will necessarily be available in subsequent releases of the driver, nor are driver version numbers guaranteed to be a linear progression. To discover if the new routines are present, it is recommended that developers attempt to make the new calls and check the result returned by the Control routine to determine if the calls are implemented rather than depend upon version numbering of the driver. If the calls are implemented, Control will return noErr; otherwise, if the calls are not implemented, Control will return controlErr.

- Enable 115.2K baud rate (csCode = 115).

- Enable 230.4K baud rate (csCode = 230).

Other configuration parameters such as bits per character, parity, and stop bits are configured by calling SerReset prior to calling the above control calls. See Technote 1018 - "Understanding the DMA Serial Driver" for details.

Applications wishing to utilize these calls should take special care to use the serial driver efficiently; not doing so will cause serious performance degradation. A good discussion of strategies for efficient use of the serial driver can be found in Technote 1018 - "Understanding the DMA Serial Driver".

Another Control call introduced with this version of the serial driver provides facilities for external clocking. This routine was designed to help support MIDI externally clocked data rates and is described in Technote 1018 - "Understanding the DMA Serial Driver."

Important:

Be aware that although the new serial driver implements XON/XOFF handshaking in a more sophisticated and efficient manner, the nature of the underlying DMA hardware makes use of this option at higher speeds (57600 bps, for example) an expensive option to implement requiring excessive interrupt processing and forgoing any possible benefits offered by the DMA chip. Apple recommends that developers utilizing software handshaking at higher transmission rates consider moving to another handshaking method when using this version of the serial driver.

Bug Fixes

The SerialDMA driver behaves correctly with interrupt-based chained read algorithms (completion routines that call Read, that have completion routines that call Read, and so on). Prior to this correction developers utilizing chained read algorithms with the DMA serial driver were required to chain calls together with intervening calls to the Deferred Task Manager.

Break conditions are now reported correctly.

The DMA Serial Driver now responds to control call 16 (bit 7) correctly, allowing DTR to remain negated when the driver is closed. Formerly, it was possible for DTR to become asserted when closing the driver, even when the client software requested otherwise by setting bit 7 to 1 in control call 16.

These bugs were not inherent in the original 68K serial driver, but were problematic in the first generation DMA Serial Driver. For a more complete listing of bug fixes present in the new DMA Serial Driver, refer to Technote 1018 - "Understanding the DMA Serial Driver."

KillIO now works correctly, resetting the appropriate internal structures for the serial drivers. Under the 68K serial driver, calling KillIO for one driver (either in or out) would reset internal variables for both drivers, possibly leaving some requests pending in the other driver's queue. For earlier versions of the serial driver, always call KillIO for both the input and the output driver when using simultaneous queued requests.

See Also:

• For information regarding serial drivers refer to the "Serial Driver" chapter and the "Device Manager" chapter of Inside Macintosh: Devices.
• For documentation discussing the new SerialDMA serial driver refer to Technote 1018 - "Understanding the DMA Serial Driver."

• Power Macintosh 9500
• Power Macintosh 8500
• Power Macintosh 7200
• Power Macintosh 7500
• PowerBook 2300
• PowerBook 5300
• PowerBook 520 (with an installed PowerPC upgrade card)
• PowerBook 540 (with an installed PowerPC upgrade card)

Note:

Previously published rules still apply for self-modifying code. Developers should call FlushInstructionCache, FlushDataCache, or FlushCodeCacheRange whenever modifying code in memory. Preferably, FlushCodeCacheRange should be used instead of FlushDataCache whenever possible to avoid unecessarily flushing the entire translation cache. BlockMove will flush the cache for blocks of data over 12 bytes in length, hence developers should use BlockMoveData when not moving code to avoid unnecessary cache flushing. Software copying PowerPC code should call MakeDataExecutable to guarantee cache coherency on split-cache processors such as the 603 and 604.

See Also:

• Technical Note HW 6 - "Cache as Cache Can"
• MC68040 32 bit microprocessor User's Manual
• Memory Management Utilities: Processor Caches (4-8 to 4-13, and 4-29 to 4-33) in Inside Macintosh: Memory
• Technical Note PT 39 - "The DR Emulator"
• "The 68LC040 Emulator" section in Inside Macintosh: PowerPC System Software (page 1-6)

Bug Fixes

The File System Manager now correctly restores an application's HiHeapMark after an asynchronous cache call.

PCI/PowerPC-based computer systems can now mount volumes larger than 4GB.

Finder Changes

Enhancements

There now exists greater than 4GB support on new PCI/PowerPC-based computer systems.

The Finder now checks in an application's resource fork for a FREF entry of type 'alis'. If such an entry exists, alias files are not resolved before they are passed to the application.

File comment information, displayed in Get Info windows, is retained across desktop file rebuilds.

On PowerPC computers, the Finder will use the translucent Drag Manager when dragging icons. Only one icon will appear translucent during a drag, even if more than one icon is selected. Interfaces and documentation are available for developers interested in incorporating translucent dragging into their applications. For more information, refer to the section Translucent Dragging of PixMaps, in this Technote.

The Name field used in Finder windows, displayed using the View by Name, View by Size, View by Kind, or View by Date options, is now wider, allowing for the longer file names to be visible when these options are selected.

For better performance, the processor cache is now flushed more intelligently on both 68040 machines and PowerPC machines.

The Copy Progress window is not updated as often during File Copy operations. This change provides better performance when large numbers of small files are copied, since the machine now spends less time drawing the progress bar than copying files. Previously, the Copy Progress window was updated as often as 30 times per second.

The Finder Update file has been built into the Finder and will no longer be present once system 7.5.3 has been installed.

The Clean Up Window command in the Special menu is no longer available while the clipboard window is active and frontmost. Previously, choosing this command while the clipboard was active would cause a crash.

If the users password has expired or needs to be changed, more meaningful error messages are displayed when attempting to use an alias to mount a server. Previous versions of the Finder simply reported that the server could not be found under these conditions.

The new Finder uses a default letter reader application for opening Powertalk mail messages if one has been specified. Under previous versions of Powertalk, if a user attempted to open a letter the creator type from the SMPLetterInfo structure was used to determine what application should be used to open the letter. This behavior is still provided, but the Finder will first check for a default letter reader application. If a default letter reader application has been defined, then that will be used to open the letter, rather than the application specified by the creator type in the SMPLetterInfo record.

Bug Fixes

Out-of-memory errors caused by emptying the trash on machines where QuickDraw GX is installed have been corrected.

Seemingly erroneous out-of-memory errors reported when attempting to open and close Finder windows should no longer occur. Users may have noticed this problem when the desktop contained few icons, a window with the Kind column was visible, and a large number of different kinds of documents had been displayed since the last restart.

The Find window will now be correctly be brought to the front if Find File is already running in the background when the Find command is chosen.

Fixed Point Math

Enhancements

Modest performance improvements have been observed in the transfer functions Fix2Frac, Fix2Long, FixRound, Long2Fix, Frac2Fix, Frac2X, and Fix2X.

Developers making extensive use of the fixed-point math facilities may want to keep the following points in mind:

• Calculations based on smaller values will execute more quickly than calculations using large values.
• Providing a value of smaller magnitude as the second argument to FixMul and FracMul will lead to better performance when these routines are called. In some cases, some of the processors will shortcut the operation if the upper bits are zero.
• Rounding and pinning still matches the previous PowerPC implementation (which is slightly different from its 68K counterpart); users of the fixed math routines, however, should not see a difference in the behavior of the package, aside from faster execution.
• QuickDraw, as well as other parts of the system, make extensive use of the fixed math routines, so developers can expect better performance when they make extensive use of these facilities.

See Also:

• The "Mathematical and Logical Utilities" chapter of Inside Macintosh: Operating System Utilities.

Bug Fixes

Hardware Cursor Support

Enhancements

Components used by the QuickTime 2.1 Image Compression Manager have been updated for compatibility with hardware cursors.

Note:

Developers drawing directly to screen devices should use the routine ShieldCursor() so their code does not conflict with the cursor.

See Also:

• The Image Compression Manager section in the "QuickTime 2.1 Developer Info" document.
• Hardware developers interested in building hardware cursor support into their products should refer to the document Designing PCI Cards and Drivers for Power Macintosh Computers.

Bug Fixes

MathLib Changes

Bug Fixes

An inaccuracy in the complementary error function erfc in the range [-0.46875,0.0] has been corrected.

Memory Manager

Enhancements

In the past, the Memory Manager would install bus error handlers during the processing of Memory Manager calls to catch invalid addresses passed to the Memory Manager routines. These bus error handlers have been removed and replaced with simple pointer sanity-checking, resulting in enhanced performance. This change is present on machines shipping with system 7.5.3 installed and is not present in the updated version of 7.5.3.

Bug Fixes

The implementation of DisableDataCache on Macintosh IIsi and IIci machines was not flushing the cache during the process of disabling it, causing compatibility problems with certain third-party 68040 expansion cards. This problem has been corrected for those machines.

See Also:

• For information regarding bus error handlers refer to Technical Note ME 14 "The New Memory Manager and You."
• Documentation regarding the above listed Memory Manager routines can be found in the "Memory Manager" chapter of Inside Macintosh: Memory.

Bug Fixes

CalcMenuSize was blindly locking and unlocking the MDEF. This caused a problem when the MDEF called CalcMenuSize, because the second call unlocked the MDEF as it was executing. The MDEF would then proceed to make other calls which might move memory. This meant the MDEF could be moved out from under itself, causing intermittent and apparently random crashes. The new CalcMenuSize corrects this problem by saving and later restoring the handle state (using HGetState and HSetState) before returning.

The new system MDEF correctly handles the case where the menu handle is an empty handle. This correction is already present in the 68K version of the Mac OS.

Monitors Control Panel

Additionally, the Monitors control panel has been extended to support both PCI- and NuBus-based Mac OS-based computer systems. Developers writing Monitors control panel Extensions should be aware of the following issues:

• Monitors control panel extensions cannot write to the 'scrn' resource. All Monitors control panel extensions should treat the screen preferences parameter as read only. Extensions that make changes to the 'scrn' resource and assume those changes have been saved are now obsolete.
• The Monitors control panel has a new gamma implementation. There is no longer a "special" gamma setting, and gamma settings are always saved. Developers creating Monitors control panel extensions should ensure that they have correctly implemented their cscGetGamma status call, since it will be called by the new control panel. If the current display gamma does not match anything in the list, Monitors control panel will add "Custom" gamma to the list indicating the current one does not match any that the video driver knows about. Developers should make certain that a cscSetGamma Control call followed by a cscGetGamma Status call returns a gamma table containing identical information: Monitors control panel byte-compares gamma tables to determine which gamma is currently set.
• Monitors control panel supports only NuBus monitors extensions.
• In the previous implementation of the Monitors control panel, the gamma list would only appear when the Option key was held down. In the new implementation, the gamma list (if one exists) is always displayed in the Options window.

See Also:

• "Creating an Extension for the Monitors Control Panel" (8-48) in the Control Panels chapter of Inside Macintosh: More Macintosh Toolbox.

Enhancements

• Improved backwards compatibility for MacTCP applications.

• There are now new options for configuring serial endpoints.
• New naming facilities for accessing additional serial ports installed with plug in cards are available.

#if defined(powerpc) || defined(__powerpc)
enum {
	uppPowerOffProcInfo = kPascalStackBased
		| RESULT_SIZE(SIZE_CODE(sizeof(OSErr)))
		| STACK_ROUTINE_PARAMETER(1, kTwoByteCode)
		| STACK_ROUTINE_PARAMETER(2, kTwoByteCode)
};
#endif

/* constants used as parameters to the power off key routine */
enum {
	kPowerKey = 0x7F,
	kDissablePwKy = 0x6B,
	kEnablePwKy = 0x00,

	kShutdownDlog = 0x7E,
	kNoDismiss = 0x00,
	kOneSecond = 0x70,
	kTenSeconds = 0x400
};

/* declaration for the power off key routine */
typedef pascal OSErr (*PwrKeyProc)(short item, short action);


OSErr DisablePowerOffKey(void) {
	OSErr err;
	PwrKeyProc pPwrKey;
	err = Gestalt('pwky', (long*) &pPwrKey);
	if (err == noErr)
#if defined(powerpc) || defined(__powerpc)
	err = CallUniversalProc((UniversalProcPtr) pPwrKey,
		uppPowerOffProcInfo, kPowerKey, kDissablePwKy);
#else
	err = pPwrKey(kPowerKey, kDissablePwKy);
#endif
	return err;
}

OSErr EnablePowerOffKey(void) {
	OSErr err;
	PwrKeyProc pPwrKey;
	err = Gestalt('pwky', (long*) &pPwrKey);
	if (err == noErr)
#if defined(powerpc) || defined(__powerpc)
		err = CallUniversalProc((UniversalProcPtr) pPwrKey,
			uppPowerOffProcInfo, kPowerKey, kEnablePwKy);
#else
		err = pPwrKey(kPowerKey, kEnablePwKy);
#endif
	return err;
}

/* SetShutdownAlertDismissal allows the caller to configure the
	shutdown alert. The ticks parameter indicates how many
	ticks before the shutdown alert is automatically dismissed.
	a value of zero disables automatic dismissal. For convenience,
	the constants kNoDismiss, kOneSecond, or kTenSeconds are provided. */
OSErr SetShutdownAlertDismissal(short ticks) {
	OSErr err;
	PwrKeyProc pPwrKey;
	err = Gestalt('pwky', (long*) &pPwrKey);
	if (err == noErr)
#if defined(powerpc) || defined(__powerpc)
		err = CallUniversalProc((UniversalProcPtr) pPwrKey,
			uppPowerOffProcInfo, kShutdownDlog, ticks);
#else
		err = pPwrKey(kShutdownDlog, ticks);
#endif
	return err;
}

#define kGestaltRMTypeIndexOrderingReverse 2	/* reverse ordering */
#define kGestaltRMTypeIndexOrderingUndefined 3	/* ordering information 
						   unavailable */