Reasons of block on open in INTERPROCESS COMMUNICATION

//U r trying to open a fifo...which does not exist...return -ve value of fd...

//U r opening fifo on one side at WR_ONLY mode...& fifo is not opened at another side at RD_ONLY mode

//then it will go at block on open ...vice versa is also possible reason

//U may open same fifo at O_RDWR mode to not to go in block on open....