3d2e39a · Idris-dev · git.iko.soy

git.iko.soy/Idris-dev

Prefix for pasting in identifiers in C FFI

commit3d2e39a14424f35c3fea3c50ab08141c2c15fe50 authorNiklas Larsson <niklas@mm.st> dateThu 23 Nov 2017, 19:49 (9 years ago) parentf8509e4

5 files changed+27−3

compare with master

unifiedsplit

docs/reference/ffi.rst+15−2 src/IRTS/CodegenC.hs+3 test/ffi007/expected+1 test/ffi007/ffi007.h+2 test/ffi007/ffi007.idr+6−1

docs/reference/ffi.rst+15−2

@@ -217,8 +217,21 @@ global variable with the following name. The type must be just ``IO Ptr``.

217217 errno : IO Ptr

218218 errno = foreign FFI_C "&errno" (IO Ptr)

219219

220−For more complicated interactions with C (such as reading and setting fields of a C struct), there is

221−a module CFFI available in the contrib package.

220+If the foreign name is prefixed by a ``#``, the name is pasted in literally. This is

221+useful to access constants that are preprocessor definitions (like ``INT_MAX``).

222+

223+..code-block:: idris

224+ %include C "limits.h"

225+

226+ -- access the preprocessor definition INT_MAX

227+ intMax : IO Int

228+ intMax = foreign FFI_C "#INT_MAX" (IO Int)

229+

230+ main : IO ()

231+ main = print !intMax

232+

233+For more complicated interactions with C (such as reading and setting fields

234+of a C struct), there is a module CFFI available in the contrib package.

222235

223236FFI implementation

224237------------------

src/IRTS/CodegenC.hs+3

@@ -314,6 +314,9 @@ bcc i (TOPBASE n) = indent i ++ "TOPBASE(" ++ show n ++ ");\n"

314314bcc i (BASETOP n) = indent i ++ "BASETOP(" ++ show n ++ ");\n"

315315bcc i STOREOLD = indent i ++ "STOREOLD;\n"

316316bcc i (OP l fn args) = indent i ++ doOp (creg l ++ " = ") fn args ++ ";\n"

317+bcc i (FOREIGNCALL l rty (FStr ('#':name)) [])

318+ = indent i ++

319+ c_irts (toFType rty) (creg l ++ " = ") name ++ ";\n"

317320bcc i (FOREIGNCALL l rty (FStr fn@('&':name)) [])

318321 = indent i ++

319322 c_irts (toFType rty) (creg l ++ " = ") fn ++ ";\n"

test/ffi007/expected+1

@@ -7,3 +7,4 @@ After calling callback

77I'm dynamic 3

886

997

10+3

test/ffi007/ffi007.h+2

@@ -1,6 +1,8 @@

11#include <stdint.h>

22typedef int (*callback)(int);

4+#define THREE 3

46int32_t testvar = 887;

68void test_ffi(int (*cb)(int));

test/ffi007/ffi007.idr+6−1

@@ -42,6 +42,10 @@ test8 : IO ()

4242test8 = foreign FFI_C "test_mulpar" (CFnPtr (Int -> Int -> ()) -> IO ())

4343 (MkCFnPtr adder)

4444

45+

46+test9 : IO Int

47+test9 = foreign FFI_C "#THREE" (IO Int)

48+

4549main : IO ()

4650main = do

4751 test

@@ -55,4 +59,5 @@ main = do

5559 i <- test7 fptr 3

5660 printLn i

5761 test8

58− pure ()

62+ printLn !test9

63+ pure ()