ionotify() readcond()

Hi all:

I want to know how to manage messaging process when i use readcond() and
ionotify() functions.
We have all runing in QNX 4.25 and using dev_read. Migrating documents says
that dev_read must be changed with devcond and ionotify (QNX 6.20), but when
you use
ionotify(), it seems to nothing happend .How we must manage this??

All your help we 'll be appreciated.