Porting windows manual-reset event to Linux?

Question

Is there any easier solution in porting a windows manual-reset event to pthread, than a pthread conditional-variable + pthread mutex + a flag if event is set or unset?

Answer 1

You can easy implement manual-reset events with pipes:

event is in triggered state -> there is something to read from the pipe

SetEvent -> write()

ResetEvent -> read()

WaitForMultipleObjects -> poll() (or select()) for reading

the "SetEvent" operation should write something (e.g. 1 byte of any value) just to put the pipe in non-empty state, so subsequent "Wait" operation, that is, poll() for data available for read will not block.

The "ResetEvent" operation will read up the data written to make sure pipe is empty again. The read-end of the pipe should be made non-blocking so that trying to reset (read from) already reset event (empty pipe) wont block - fcntl(pipe_out, F_SETFL, O_NONBLOCK) Since there may be more than 1 SetEvents before the ResetEvent, you should code it so that it reads as many bytes as there are in the pipe:

char buf[256]; // 256 is arbitrary
while( read(pipe_out, buf, sizeof(buf)) == sizeof(buf));

Note that waiting for the event does not read from the pipe and hence the "event" will remain in triggered state until the reset operation.