This .NET enum wraps the AcDb::OsnapMask ObjectARX enum.

Public Enum ObjectSnapMasks
  AllowTangent = &H20000
  ApparentIntersection = &H800
  Center = 4
  DisablePerpendicular = &H40000
  End = 1
  Immediate = &H10000
  Insertion = &H40
  Intersection = &H20
  Middle = 2
  Near = &H200
  Node = 8
  NoneOverride = &H200000
  Perpendicular = &H80
  Quadrant = &H10
  Quick = &H400
  RelativeCartesian = &H80000
  RelativePolar = &H100000
  Tangent = &H100
End Enum

public enum ObjectSnapMasks {
  AllowTangent = 0x20000,
  ApparentIntersection = 0x800,
  Center = 4,
  DisablePerpendicular = 0x40000,
  End = 1,
  Immediate = 0x10000,
  Insertion = 0x40,
  Intersection = 0x20,
  Middle = 2,
  Near = 0x200,
  Node = 8,
  NoneOverride = 0x200000,
  Perpendicular = 0x80,
  Quadrant = 0x10,
  Quick = 0x400,
  RelativeCartesian = 0x80000,
  RelativePolar = 0x100000,
  Tangent = 0x100
}