you mixed up reading and writing,
reading requires two parameters (which pipe# to open, 0-5 and the 40-bit address of the pipe to open) whereas writing only requires the 40-bit address of the pipe to open
you mixed up reading and writing,
reading requires two parameters (which pipe# to open, 0-5 and the 40-bit address of the pipe to open) whereas writing only requires the 40-bit address of the pipe to open