Re: [PATCH 2/3] signalfd: add ability to return siginfo in a raw format (v2)

2013/1/19 Michael Kerrisk (man-pages) [off-list ref]:

quoted

As SFD_RAW is being added to the kernel API we should document it.
Please keep Michael cc'ed and work with him on getting the manpages
updated.

The API is certainly no thing of beauty, as I already remarked here:
http://thread.gmane.org/gmane.linux.file-systems/70420/focus=1420228

All of us have similar thoughts, but we don't know a better solution.

Here is an example of usage signalfd and pread:
http://lists.openvz.org/pipermail/criu/2013-January/007040.html

A description of the API can be found here:
https://lwn.net/Articles/531939/

Thanks you for the attempt to involve more people to this discussion.

The main problem is the ugliness of changing the meaning of pread()'s
'offset' argument to be a multiplexed [signal queue selector + queue
position].

I do wonder if we can do better, though I have no particular solution
to offer beyond the sledgehammer of adding a new system call.

If we are choosing between this interface or a new syscall, I would
prefer this interface. signalfd is a special descriptor, so I think it
is not a big deal, that it works a bit strange. If all other would
decides, that a new syscall is better, I will not ague.

Michael, thank you for the comments.

Cheers,

Michael


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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