"Dean Herington"
On Wed, 26 Feb 2003, Sigbjorn Finne wrote:
wait3() or getrusage()? (Neither of which are supported by the posix library.)
--sigbjorn
Thanks, Sigbjorn. I drafted a Haskell wrapping of wait4(), modeled on code I found in CVS. See attached. I'd like a bit of help in two respects:
1. I found it difficult to satisfy the code requirements because I'm building the module outside the RTS build environment. Some issues:
a. I don't know how to make a .hsc file, which would be the appropriate form for the file, I think. This meant I couldn't use #const, and may also explain why I couldn't find the __hsunix_* routines.
The HsUnix.h contain these helper routines, which you'll find in the include/ subdir of the unix package.
c. I'm not sure how to define `struct timeval` and `struct rusage` so I can avoid the kludgy code in `makeProcessResourceUsage`.
hsc2hs does let you access fields of a struct without having to know offsets nor struct sizes (cf. getProcessTimes in Process.hsc)
It seems that maybe I should be building in the RTS environment (and maybe even extending the System.Posix.Process module itself) to clean up all of the above problems. That seems a bit daunting to me, however.
That makes good sense. If you're over the hurdle of setting up and building the fptools tree, there's really not much to it. Modify libraries/unix/System/Posix/Process.hsc followed by a 'make' in libraries/unix. It uses the in-tree version of hsc2hs, so you don't have to worry about setting it up.
2. Having gotten my module to compile cleanly, it--not surprisingly--fails at runtime:
invalid argument Action: reapChildProcess Reason: Invalid argument
I can't see anything obviously wrong with the parameters, I'm assuming the pid and the options settings are correct. Tracing the system calls will probably give you some useful info. --sigbjorn