python - put a pipe in a dictionary -

pmu_pipe_map = {}  pipe= 'tmp/%s.pipe' % hostname if not os.path.exists(pipe):     os.mkfifo(pipe)  pmu_pipe_map[hostname] = os.open(pipe, os.o_wronly) 

im trying open n pipes. in order keep track of them i'd store them somehow - in dictionary - thought above code should work freezes during execution. suggestions?

this work however:

pipein = os.open(pipe, os.o_wronly) 

aha! apparently there has read on other end before can return pipe. question asked not correct because failed test 2 scenarios in same way. problem in understanding how pipes work. in situation dictionary entry succeed once piping opened on 'read' end block until then. how determine if pipe can written