Consider O_CLOEXEC when opening FIFOs?

[fandahao17]

Hi there! Thanks for your awesome project!

This is how I run into this problem: In main(), I started notification on FIFO /dev/pigpio0 and forked another process which runs pig2vcd to output the captured waveform. But I found that in the child process, I can't close /dev/pigpio0 even if I called gpioNotifyClose.

After going through the source code I found that by default, the actual close is done in the alert thread, but fork() only copies the main thread. I read the man page and found that this problem can be fixed by including O_CLOEXEC when calling open(). Will you consider adding this flag when opening FIFOs?

[guymcswain]

As an alternative approach, you could use pigpiod_if2 to open notifications via the socket then fork pig2vcd from there.

[joan2937]

I don't have any problem with the use of this flag. Mind you I have only had a quick skim through the man pages.

[guymcswain]

@fandahao17 , if you have a working proposal with test cases, please submit a pull request.