A question about `PROCESSX_INTERRUPT_INTERVAL`

[king-of-poppk]

This value is hardcoded here:

processx/src/processx.h

Line 78 in 6a16b63

#define PROCESSX_INTERRUPT_INTERVAL 200

Is my understanding correct that this interval is there only to allow the interruption of the polling and in no way adds a (significant, i.e. proportional to its value) delay to the time it takes for, let's say, p$poll_io(-1) to return?

AFAIU processx leverages native libraries to provide overhead-less IO event forwarding (modulo interruptability). See:

• UNIX:

  processx/src/processx-connection.c

  Line 1965 in 6a16b63

  ret = poll(fds, nfds, PROCESSX_INTERRUPT_INTERVAL);

  • https://man7.org/linux/man-pages/man2/poll.2.html
• Windows:

  processx/src/processx-connection.c

  Lines 1154 to 1160 in 6a16b63

  	if (selj == 0) {
  	sres = processx__thread_getstatus(&bytes, &key, &overlapped,
  	poll_timeout);
  	} else {
  	sres = processx__thread_getstatus_select(&bytes, &key, &overlapped,
  	poll_timeout);
  	}

  • processx/src/win/thread.c

    Lines 133 to 138 in 6a16b63

    	DWORD res = GetQueuedCompletionStatus(
    	iocp,
    	processx__thread_getstatus_data.lpNumberOfBytes,
    	processx__thread_getstatus_data.lpCompletionKey,
    	processx__thread_getstatus_data.lpOverlapped,
    	processx__thread_getstatus_data.dwMilliseconds);

    • https://learn.microsoft.com/en-us/windows/win32/api/ioapiset/nf-ioapiset-getqueuedcompletionstatus

[gaborcsardi]

Is my understanding correct that this interval is there only to allow the interruption of the polling and in no way adds a (significant, i.e. proportional to its value) delay to the time it takes for, let's say, p$poll_io(-1) to return?

Sorry for the late reply. You are indeed correct. processx will return as soon as there is output available on the pipe (or the pipe is closed, etc.) The 200 ms is only for checking for CTRL+C from the user.