Converting GL blend mode to non GL

Given the gl blend mode is defined as:

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

what would be the equivalent SDL standard blend mode (SDL_BLENDMODE_ADD) ?

or if making a custom blend would that be equal to:

SDL_ComposeCustomBlendMode(
SDL_BLENDFACTOR_SRC_ALPHA,
SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
SDL_BLENDOPERATION_ADD,
SDL_BLENDFACTOR_ONE,
SDL_BLENDFACTOR_ZERO,
SDL_BLENDOPERATION_ADD)

Any help appreciated!