| Previous | Next |
| KERN_MEMORY_DATA_MOVED | KERN_INVALID_PROCESSOR_SET |
KERN_MEMORY_RESTART_COPY
KERN_MEMORY_RESTART_COPY is an internal Mach memory-object result. XNU documents it for a strategic copy attempt where a quicker copy has become possible; the caller should restart with the kernel's quick-copy path. XNU also states that this code is seen only by the kernel.
It is therefore not a normal macOS application failure, even though a tool may display the constant name while decoding low-level logs or headers. Its presence describes an optimization and control-flow decision inside Mach's copy machinery, not data loss or an invalid user buffer.
How to interpret it
- For ordinary application code: look for the higher-level API result, because this return is not intended to cross that boundary.
- For kernel or pager work: preserve the retry/restart semantics rather than treating it as a terminal error.
- For diagnostics: associate it with memory-object copy strategy and copy-on-write behavior, not with filesystem copy operations.
Mach virtual memory uses memory objects and delayed copying to avoid unnecessary data duplication. This return code is part of that internal optimization machinery and is useful mainly when reading kernel source or debugging the memory-management subsystem.
References
About “What is” service
Many of users are faced with the problem of interpreting errors that occur during the work of operating systems. In some cases, the operating system reports that an error has occurred and displays only an integer error code value. Often it is difficult to even roughly understand the cause of the error from the information given out. Our “what is” service contains a database of errors in Windows, Linux, Macos and Solaris operating systems. The database contains tens of thousands of values. In most cases, the online service will be able to help with the definition of the short name of the error and its detailed description.
Categories
Current version of service supports following types of error and status codes:
| NTSTATUS | Many kernel-mode standard driver routines and driver support routines use the NTSTATUS type for return values. Additionally, drivers provide an NTSTATUS-typed value in an IRP’s IO_STATUS_BLOCK structure when completing IRPs. The NTSTATUS type is defined in Ntdef.h, and system-supplied status codes are defined in Ntstatus.h. |
| Win32 error | Win32 error codes MUST be in the range 0x0000 to 0xFFFF, although Win32 error codes can be used both in 16-bit fields (such as within the HRESULT type specified in section in this article) as well as 32-bit fields. Most values also have a default message defined, which can be used to map the value to a human-readable text message; when this is done, the Win32 error code is also known as a message identifier. |
| HRESULT | HRESULT is a data type used in Windows operating systems, and the earlier IBM/Microsoft OS/2 operating system, to represent error conditions, and warning conditions. The original purpose of HRESULTs was to formally lay out ranges of error codes for both public and Microsoft internal use in order to prevent collisions between error codes in different subsystems of the OS/2 operating system. HRESULTs are numerical error codes. Various bits within an HRESULT encode information about the nature of the error code, and where it came from. HRESULT error codes are most commonly encountered in COM programming, where they form the basis for a standardized COM error handling convention. |
| HTTP Status Code | Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The message phrases shown are typical, but any human-readable alternative may be provided. |
| errno | Integer value, which is returned by system calls and some library functions in the event of an error to indicate what went wrong. errno is defined by the ISO C standard to be a modifiable lvalue of type int, and must not be explicitly declared; errno may be a macro. errno is thread-local; setting it in one thread does not affect its value in any other thread. |
| Kern Return | Apple Kernel return codes. |
| Ipp Status | The IppStatus constant enumerates the status values returned by the Intel IPP functions, indicating whether the operation is error-free. |
Source code
The service is based on the open source library AllStat. Its sources are available on our git server. We will be grateful for your participation in the finalization of the library and ideas for the development of the service. You can also download ErrorLookup utility and libraries from our site.