BlendOperation works?

SDL Development
1
  1. SDL_ComposeCustomBlendMode on Windows does not work, the previously selected operation is performed instead.
  2. SDL_BLENDOPERATION_SUBTRACT - I don’t see any effect
  3. SDL_BLENDOPERATION_REV_SUBTRACT works as SDL_BLENDOPERATION_SUBTRACT should

Are these operations dependent on hardware or SDL designers? For example, BlendFactor is multiplied, which has no effect on black. For example, I don’t know how to get the XOR effect …