typedef enum _WHEA_ERROR_SOURCE_TYPE
{
         WheaErrSrcTypeMCE = 0,
         WheaErrSrcTypeCMC = 1,
         WheaErrSrcTypeCPE = 2,
         WheaErrSrcTypeNMI = 3,
         WheaErrSrcTypePCIe = 4,
         WheaErrSrcTypeOther = 5,
         WheaErrSrcTypeMax = 6
} WHEA_ERROR_SOURCE_TYPE;

Windows Vista Kernel Structures