SYSTEM_EXCEPTION_INFORMATION

The SYSTEM_EXCEPTION_INFORMATION structure is what a successful call to ZwQuerySystemInformation or NtQuerySystemInformation produces in its output buffer when given the information class SystemExceptionInformation (0x21).

Documentation Status

The SYSTEM_EXCEPTION_INFORMATION structure is defined in WINTERNL.H from the Software Development Kit (SDK). The definition there has the whole structure as one array of bytes, named Reserved1. Documentation of NtQuerySystemInformation describes the structure as “opaque” and suggests that whatever is produced in it for the SystemExceptionInformation case “can be used to generate an unpredictable seed for a random number generator.”

Layout

The SYSTEM_EXCEPTION_INFORMATION is 0x10 bytes in both 32-bit and 64-bit Windows.

Offset Definition
0x00
ULONG AlignmentFixupCount;
0x04
ULONG ExceptionDispatchCount;
0x08
ULONG FloatingEmulationCount;
0x0C
ULONG ByteWordEmulationCount;