HRESULT

In the field of computer programming, the 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.

The HRESULT numbering space is vendor-extensible. Vendors can supply their own values for this field, as long as the C bit (0x20000000) is set, indicating it is a customer code.

The HRESULT numbering space has the following internal structure. Any protocol that uses NTSTATUS values on the wire is responsible for stating the order in which the bytes are placed on the wire.

S (1 bit): Severity. If set, indicates a failure result. If clear, indicates a success result.

R (1 bit): Reserved. If the N bit is clear, this bit MUST be set to 0. If the N bit is set, this bit is defined by the NTSTATUS numbering space.

C (1 bit): Customer. This bit specifies if the value is customer-defined or Microsoft-defined. The bit is set for customer-defined values and clear for Microsoft-defined values.

N (1 bit): If set, indicates that the error code is an NTSTATUS value (as specified in section 2.3), except that this bit is set.

X (1 bit):  Reserved.  SHOULD be set to 0.

Facility (11 bits): An indicator of the source of the error. New facilities are occasionally added by Microsoft.

The following table lists the currently defined facility
codes:

Code (2 bytes): The remainder of the error code.

HRESULT status codes are supported by our What Is service.