Re: [GHC] #11697: rts/posix/Itimer.c: ignoring return value of ‘read’

[GHC]

#11697: rts/posix/Itimer.c: ignoring return value of ‘read’
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        Reporter:  erikd             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Runtime System    |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by erikd:

@@ -27,0 +27,3 @@
+
+ This seems to be a warning that only occurs on Ubuntu, because the Ubuntu
+ libc has marked the `read` function as `warn_unused_result`.

New description:

 Builds currently failing in travis. Eg : https://travis-
 ci.org/ghc/ghc/jobs/115023819

 {{{
 rts/posix/Itimer.c: In function ‘itimer_thread_func’:
 rts/posix/Itimer.c:205:17: error:
      error: ignoring return value of ‘read’, declared with attribute
      warn_unused_result [-Werror=unused-result]
 }}}

 The code being complained about is:

 {{{
         if (USE_TIMERFD_FOR_ITIMER) {
             read(timerfd, &nticks, sizeof(nticks));
         } else {
 }}}

 The value of `nticks` is never used, so a solution to this may be:

 {{{
         if (USE_TIMERFD_FOR_ITIMER) {
             if (read(timerfd, &nticks, sizeof(nticks)) != sizeof(nticks))
                                 nticks = 0;
         } else {
 }}}

 This seems to be a warning that only occurs on Ubuntu, because the Ubuntu
 libc has marked the `read` function as `warn_unused_result`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11697#comment:2>
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