Interpreted an int64_t typedef as CInt

[ian-ross]

Bug imported from C2HS Trac

Trac ticket created: 2012-07-04T19:07:40-0700; last modified: 2012-07-05T00:16:38-0700

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Priority: blocker

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A library I'd like to write bindings to has a typedef of int64_t to a library-specific type name. c2hs seems to interpret that type as CInt, both in foreign import declarations and in {# type #} directives. It should interpret that type as a 64-bit integer type instead.

[ian-ross]

Original comment date: 2012-07-05T00:16:38-0700

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I managed to track down the problem. Turns out that the header in question indirectly includes <sys/types.h> before it includes <stdint.h>, and <sys/types.h> defines int64_t in a way that c2hs doesn't know how to handle:

$ cpp /usr/include/stdint.h | grep -w int64_t
typedef long int int64_t;
$ cpp /usr/include/sys/types.h | grep -w int64_t
typedef int int64_t __attribute__ ((__mode__ (__DI__)));

I'd guess that c2hs ignores the GCC-specific attribute that
overrides the size, and just sees "int".

[ian-ross]

The HEAD version of C2HS now has the capability to deal with this: you can use a typedef hook to explicitly associate the C int64_t typedef with an appropriate Haskell type -- because the C parser that we use doesn't understand the GCC-specific storage mode attributes, it's necessary to make this association explicitly within your .chs file, but at least it's now possible. See the test case for this issue to see how it works.