[GHC] #16226: printf g format specifier doesn't match the C standard behaviour

23 Jan 2019

      #16226: printf g format specifier doesn't match the C standard behaviour
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           Reporter:  Fuuzetsu       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Core           |           Version:  8.6.3
  Libraries                          |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 {{{
 [nix-shell:/tmp]$ clang printg.c && ./a.out && cat printg.c
 3122.55
 #include 
 int main(void) {
   printf("%.16g\n", 3122.55);
 }

 [nix-shell:/tmp]$ runhaskell printg.hs && cat printg.hs
 3122.5500000000000000
 import Text.Printf (printf)
 main = printf "%.16g\n" (3122.55 :: Double)
 }}}

 Some more info here https://stackoverflow.com/questions/54162152/what-
 precisely-does-the-g-printf-specifier-mean

 Notably I'd expect GHC to give me the same answer as the shown C program.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16226
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