During development, it may be desirable to copy data to and from the Indy host to the game. For example, a MIDI sequence could be repeatedly edited on the host and then played on the N64. Of course this could be accomplished by recreating and downloading the image repeatedly, but the design cycle could be reduced significantly by simply copying the new sequence to the N64 while the application is still running.
For these applications, a host side, as well as a game side API is provided. The game side interfaces are as always defined by including /usr/include/ultra64.h and linking with /usr/lib/libultra[_d].a. The host side interfaces are declared in /usr/include/ultrahost.h and defined in /usr/lib/ultrahost.a.