January 2011 - C2hs - Haskell.org

timespec and c2hs
by Erik Hesselink 21 Apr '11

21 Apr '11

Hi, I'm trying to write a Storable instance for timespec using c2hs. Since timespec is defined something like: struct timespec { time_t tv_sec; long tv_nsec; }; I've defined the following in Haskell: #include <sys/time.h> #c typedef struct timespec timespec_t; #endc data TimeSpec = TimeSpec { seconds :: CTime , nanoseconds :: CLong } instance Storable TimeSpec where peek t = TimeSpec <$> {#get timespec_t->tv_sec #} t <*> {#get timespec_t->tv_nsec#} t ... However, this fails to compile. For tv_sec, c2hs generates "peekByteOff ptr 0 :: IO CLong" instead of "IO CTime". Why is this? Am I doing something wrong, or is there a bug/missing feature in c2hs? Erik

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[c2hs] #36: Allow parametrized yet monomorphic data types in {#pointer ... #}
by c2hs 26 Jan '11

26 Jan '11

#36: Allow parametrized yet monomorphic data types in {#pointer ... #} --------------------+------------------------------------------------------- Reporter: guest | Type: enhancement Status: new | Priority: normal Milestone: | Component: general Version: 0.16.2 | Keywords: --------------------+------------------------------------------------------- Hello. Currently pointer declaration could only use non-parametrized types. But sometimes it's too restrictive. I think examples below are self- explanatory: This is OK but pointer is untyped {{{ {#pointer *OKA__Hit as OKA_Hit #} }}} This doesn't work although it's perfectly sound. On syntactic level it may require addition of parenthesis. {{{ {#pointer *OKA__Hit as OKA_Hit -> Hit Chan () #} ./Event.chs:23: (column 42) [ERROR] >>> Syntax error! The phrase `Chan' is not allowed here. }}} There is workaround with type synonyms but it's not very elegant. {{{ type Typedef = Hit Chan () {#pointer *OKA__Hit as OKA_Hit -> Typedef #} }}} -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/36> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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Re: [C2hs] [c2hs] #9: sizeof computation fails for nested derived types (pointer to array or array of pointers)
by c2hs 19 Jan '11

19 Jan '11

#9: sizeof computation fails for nested derived types (pointer to array or array of pointers) --------------------+------------------------------------------------------- Reporter: guest | Type: defect Status: new | Priority: normal Milestone: | Component: general Version: 0.15.1 | Keywords: --------------------+------------------------------------------------------- Comment(by guest): I think this may be related: bug.h {{{ typedef char inner_t[32]; typedef struct { inner_t first; inner_t second; } outer_t; }}} bug.chs {{{ module Bug where #include "bug.h" main :: IO () main = print ({# sizeof inner_t #}, {# sizeof outer_t #}) }}} Running c2hs bug.chs (on a 64-bit machine) gives me… {{{ module Bug where main :: IO () main = print (32, 16) }}} Shurely schome mischtake? On the other hand, okay.h {{{ typedef struct { char first[32]; char second[32]; } outer_t; }}} okay.chs {{{ module Okay where #include "okay.h" main :: IO () main = print {# sizeof outer_t #} }}} gives… {{{ module Okay where main :: IO () main = print 64 }}} -- Ticket URL: <http://hackage.haskell.org/trac/c2hs/ticket/9#comment:1> c2hs <http://www.cse.unsw.edu.au/~chak/haskell/c2hs/> C->Haskell, An Interface Generator for Haskell

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