Having a trouble with opening FIFO in C

问题

I'm having a trouble in opening FIFOs in C.. first I created them using mkfifo() function with permission : 0777, and when I tried to open them, it succeeded in opening the first FIFO only, then the process will stuck in opening the second FIFO, and this is my code :

fd1 = open("FIFO1_PATH", O_WRONLY );
fd2 = open("FIFO2_PATH", O_WRONLY );

This will not be executed, but once I comment the second line, it executes ! Is there a limit for the number of opening FIFOs per process ? I don't know why is this happening.. I just spent 3 Hours trying to figure out what the problem is, but without any results :(

回答1:

To answer you question about limits - default in Linux is 1024 file descriptors for a process. Your problem is probably not opening the second FIFO for reading so open for writing blocks.

回答2:

I just got it right :)

I have to let the opening process wait until some other process opens the FIFO for reading (and it will be a blocked reading).. by doing sleep on the writing process I will ensure that the other process will opens for reading ..

来源：https://stackoverflow.com/questions/4561925/having-a-trouble-with-opening-fifo-in-c