| ID and name |
Explanation |
| 1 (Bus error) |
A memory reference was
invalid. This is the most common type of system error.
An application might have tried to access memory in another
application's partition or in a portion of memory not accessible
to the application. Typically, this error occurs if your application
uses a handle or pointer reference that is no longer valid or
was never valid. For example, if your application does not initialize
a variable of type Handle or Ptr to
the correct value and then tries to use that value as a memory
reference, a bus error could occur. Or if you have made an error
in performing pointer arithmetic, a bus error could occur. This
error could also occur if your application attempts to access
a block of memory that has been moved or disposed of. Once your
application disposes of a block of memory, either directly or
indirectly, all pointer and handle references to that block
of memory are invalid and could cause bus errors. If your application
dereferences a handle, calls a routine that could move or purge
memory, and then relies on the master pointer value, a bus error
could occur. If your application is careless in using the Memory
Manager's BlockMove procedure or another technique
to copy bytes directly, data structures used by the Memory Manager
could be altered and a bus error generated. |
| 2 (Address error) |
A reference to a word (2 bytes) or
long word (4 bytes) was not on a word boundary. An address
error is often simply a bus error in which the memory reference
happens to be odd. Thus, any programming errors that could cause
a bus error might result in an address error as well. Indeed,
sometimes the same programming error can generate both types
of errors if you execute the offending code several times. Address
errors are often microprocessor-specific. That is, code that
executes correctly on MC68030 microprocessors might generate
an address error on MC68000 microprocessors. This is most likely
to be a problem for assembly-language programmers. |
| 3 (Illegal instruction) |
The microprocessor attempted to execute
an instruction not defined for that version of the microprocessor.
This might occur if you set a compiler to generate MC68030 code
and then attempt to execute that code on a MC68000 microprocessor.
Attempting to execute PowerPC code on a MC680x0 microprocessor
could also cause this problem. Typically, this problem
occurs only if you are programming in assembly language or if
your compiler generates illegal instructions. If your application
(either intentionally or unintentionally) modifies its own code
while executing, then this problem could also occur. |
| 4 (Zero divide) |
The microprocessor received a signed divide (DIVS)
or unsigned divide (DIVU) instruction, but the
divisor was 0. When you write code that performs the division
operation, you should ensure that the divisor can never be 0,
unless you are using Operating System or SANE numeric types
that support division by 0. |
| 5 (Check exception) |
The microprocessor executed a check-register-against-bounds
(CHK) instruction and detected an out-of-bounds
value. If you are programming in a high-level language, this
might occur if you have enabled range-checking and a value is
out of range (for example, you attempt to access the sixth element
of a five-element array). |
| 6 (TrapV exception) |
The microprocessor executed a trap-on-overflow (TRAPV)
instruction and detected an overflow. If you are programming
in a high-level language, this might occur if you have enabled
integer-arithmetic overflow checking and an overflow occurs.
|
| 7 (Privilege violation) |
The Macintosh computer was in a mode that did not allow execution
of the specified microprocessor instruction. This should not
happen because the Macintosh computer always runs in supervisor
mode. However, if you are programming in assembly language,
this error could occur if you execute an erroneous return-from-execution
(RTE) instruction. |
| 8 (Trace exception) |
The trace bit in the status register is set. Debuggers use
this error to force code execution to stop at a certain point.
If you are programming in a high-level language, this system
error should always be intercepted by your low-level debugger.
|
| 9 (A-line exception) |
The trap dispatcher failed to execute the specified system
software routine. This error might occur if you attempt to execute
a Toolbox routine that is not defined in the version of the
system software that is running. |
| 10 (F-line exception) |
Your application executed an illegal instruction. |
| 11 (Miscellaneous exception) |
The microprocessor invoked an exception not covered by system
error IDs 1 to 10. This exception might be generated in the
case of a hardware failure. |
| 12 (Unimplemented core routine) |
The Operating System encountered an unimplemented trap number.
|
| 13 (Spurious interrupt) |
The interrupt vector table entry for a particular level of
interrupt is NIL. This error usually occurs with
level 4, 5, 6, or 7 interrupts. Typically, this error should
affect only developers of low-level device drivers, NuBus cards,
and other expansion devices. |
| 14 (I/O system error) |
A Device Manager or Operating System queue operation failed.
This might occur if the File Manager attempts to remove an entry
from an I/O request queue, but the queue entry has an invalid
queue type (perhaps the queue entry is unlocked). Or this might
occur as a result of a call to Fetch or Stash,
but the dCtlQHead field was NIL. This
error can also occur if your driver has purged a needed device
control entry (DCE). |
| 15 (Segment loader error) |
A call was made to load a code segment, but a call to GetResource
to read the segment into memory failed. This could occur if
your application attempts to load a segment that does not exist,
or if your application attempts to load a segment but there
is not enough memory for it in the application heap. When an
attempt to load a code resource with resource ID 0 fails, a
system error with ID 26 is generated instead. |
| 16 (Floating-point error) |
The halt bit in the floating-point environment word was set.
|
| 17-24 (Can't load package) |
The Package Manager attempted to load a package into memory,
but the call to GetResource failed. This could
occur because the system file is corrupted, or because there
is not enough memory for the package to be loaded. For example,
if you call a List Manager routine when memory is very low,
the SysError procedure could be executed. |
| 25 (Out of memory) |
The requested memory block could not
be allocated in the heap because there is insufficient free
space. Typically, a Toolbox routine generates this system error
if it requires heap space to run but there is insufficient space.
Your application should prevent this from occurring by ensuring
that it always leaves enough memory for Toolbox operations.
You can also get this error
if the Package Manager was unable to load the Apple Event Manager
(Pack 8). See the chapter "Package Manager" in this book for
an explanation of this error. |
| 26 (Segment loader error) |
A call was made to load a code segment
with resource ID 0, but the call to GetResource
failed. This usually occurs if your application attempts to
execute a nonexecutable file. You can also get this
error if the Package Manager was unable to load the Program-to-Program
Communications (PPC) Toolbox package (Pack 9). See the chapter
"Package Manager" in this book for an explanation of this error.
|
| 27 (File map destroyed) |
The File Manager encountered a paradox. A logical block number
was found that is greater than the number of the last logical
block on the volume or less than the logical block number of
the first allocation block on the volume. The disk is probably
corrupted. |
| 28 (Stack overflow error) |
The Operating System detected that
the application's stack collided with its heap. This could happen
when a deeply nested routine is executed or when interrupt routines
use more stack space than available. If your application relies
on recursion, it should monitor the size of the stack to prevent
such an error from occurring. If this error occurs simply
because your application attempted to execute a deeply nested
routine, you can prevent this from occurring by increasing the
minimum size of the stack at application startup. Because the
size of the stack may differ from one Macintosh model to another,
an application might encounter no problems on a Macintosh LC
but crash on a Macintosh Plus, for example. You can also get
this error if the Package Manager was unable to load the Edition
Manager (Pack 11). See the chapter "Package Manager" in this
book for an explanation of this error. |
| 30 (Disk insertion required) |
A necessary disk is not available.
The System Error Handler responds to this error by requesting
that the user insert the requested disk. Often, the user can
cancel this alert box by pressing Command-period repeatedly;
in certain circumstances, however, pressing Command-period repeatedly
can lead to a system crash. You can also get this error
if the Package Manager was unable to load the Data Access Manager
(Pack 13). See the chapter "Package Manager" in this book for
an explanation of this error. |
| 31 (Wrong disk inserted) |
The user inserted the incorrect disk
in response to a disk-insertion request. The System Error Handler
ejects the disk and allows the user to insert another.
You can also get this error if the Package Manager was unable
to load the Help Manager (Pack 14). See the chapter "Package
Manager" in this book for an explanation of this error. |
33 (Negative zcbFree value) |
The Memory Manager's calculation of the number of bytes free
in a heap zone (that is, the value of the zcbFree
field) resulted in a negative number. Your application might
have used up too much memory in the heap zone, or the heap is
corrupted |
| 41 (Finder not found) |
The Operating System could not locate the Finder on the disk.
The disk might be corrupted. |
| 84 (Menu purged) |
The Menu Manager attempted to access information about a menu,
but the menu record was purged. You should ensure that all menus
stored in your application's resource file are marked as unpurgeable.
|
| 100 (Can't mount system startup volume) |
The Operating System could not mount the system startup volume
and thus is unable to read the system resource file into memory.
The startup volume could be corrupted or broken. Your application
can force startup on another volume by clearing parameter RAM,
as discussed in the chapter "Parameter RAM Utilities" in this
book. |
| 32767 (Default system error) |
This is the default system error that executes when an undefined
problem occurs. Your application can call the SysError
procedure with this value. |
