Error on undefined typedef union

[rschwarz]

I have something like this in my C header (similar to #58):

typedef union secretunion SECRET;

When I try to wrap this, I actually get an error:

[ Info: Error thrown. Last cursor available in Clang.wrap_c.debug_cursors
ERROR: LoadError: BoundsError: attempt to access 0-element Array{Clang.cindex.CLCursor,1} at index [0]
Stacktrace:
 [1] getindex at ./array.jl:731 [inlined]
 [2] largestfield(::Clang.cindex.UnionDecl) at Clang/src/wrap_c.jl:312
 [...]
 [5] wrap(::Clang.wrap_c.WrapContext, ::OrderedCollections.OrderedDict{Symbol,Clang.wrap_c.ExprUnit}, ::Clang.cindex.UnionDecl) at Clang/src/wrap_c.jl:436
 [6] wrap_header(::Clang.wrap_c.WrapContext, ::Clang.cindex.TranslationUnit, ::String, ::Array{Any,1}) at Clang/src/wrap_c.jl:685
 [...]

The problem seems to be that largestfield tries to return access fields[0] while fields is actually empty:

function largestfield(cu::UnionDecl)
    maxsize,maxelem = 0,0
    fields = children(cu)
    for i in 1:length(fields)
        field_size = typesize(cu_type(fields[i]))
        if field_size > maxsize
            maxsize = field_size
            maxelem = i
        end
    end
    fields[maxelem]
end

[rschwarz]

Maybe related to #55.

[Gnimuc]

that's because opaque union typedefs were not handled correctly.

[rschwarz]

Thanks for your proper fix, I will try again with your branch.

[rschwarz]

@Gnimuc I tried running my script again using your branch refactor. I modified it a bit to look like the example you give in the README.md:

wc = Clang.init(
    headers=[joinpath(header_path, h) for h in headers],
    header_wrapped = (root, current) -> root == current,
    header_library = x -> "libscip",
    common_file="common.jl",
    output_dir="../src/wrapper",
    clang_includes = vcat(LIBCLANG_INCLUDE, LLVM_INCLUDE),
    clang_args = ["-I", joinpath(LIBCLANG_INCLUDE, "..")],
    clang_diagnostics = true,
)

Clang.run(wc)

Here, headers will contain absolute paths to the header files. When I run this, I get an error right in the beginning (for the first header file in the array):

[ Info: wrapping header: /usr/include/scip/type_retcode.h ...
ERROR: LoadError: ArgumentError: invalid index: /usr/include/scip/type_retcode.h of type String
Stacktrace:
 [1] to_index(::String) at ./indices.jl:265
 [2] to_index(::Array{TranslationUnit,1}, ::String) at ./indices.jl:247
 [3] to_indices at ./indices.jl:293 [inlined]
 [4] to_indices at ./indices.jl:290 [inlined]
 [5] getindex at ./abstractarray.jl:905 [inlined]
 [6] run(::WrapContext) at /home/rs/.julia/dev/Clang/src/compat.jl:100

The line at level 6 is indeed a little strange: In ctx.trans_units[header], header is a String, while ctx.trans_units is an Array. How could it be used as an index?

Maybe I got something wrong, but I could not find an example or test that uses init and run like in the README.

[Gnimuc]

oh, nice catch. I forgot to update the run(wc::WrapContext) function. a2c95f9

@leethargo init and run are old high-level APIs. If you'd like to know what Clang does under the hood, please take a look at this tutorial. The generator script of Clang.jl is also a good example on how to use Clang.

[Gnimuc]

note, you should replace LIBCLANG_INCLUDE with your lib's header path:

wc = Clang.init(
    headers=[joinpath(header_path, h) for h in headers],
    header_wrapped = (root, current) -> root == current,
    header_library = x -> "libscip",
    common_file="common.jl",
    output_dir="../src/wrapper",
    clang_includes = vcat(header_path, LLVM_INCLUDE),
    clang_args = ["-I", header_path],
    clang_diagnostics = true,
)

[rschwarz]

Thanks again. I might look into the tutorial later, when I need more fine-grained control, but your snippet already helped me generate a wrapper for the whole set of headers I care about!

I thought that LIBCLANG_INCLUDE was needed to provide stdef.h and similar, but I guess that LLVM_INCLUDE will do that then.

[Gnimuc]

I thought that LIBCLANG_INCLUDE was needed to provide stdef.h and similar, but I guess that LLVM_INCLUDE will do that then.

Exactly.

Here is another hint for generating a template wrapper project:

copydeps(dirname(api_file))
print_template(joinpath(dirname(api_file), "LibTemplate.jl"))