There is no definition for dispatch_data_t

[Gnimuc]

Discussed in #497

^{Originally posted by maleadt June 18, 2024}
I'm trying to wrap some macOS C header, which has the following:

#ifdef __APPLE__
#import <dispatch/dispatch.h>
#endif // __APPLE__

That header apparently has issues with Clang.jl, leading to:

[ Info: Building the DAG...
┌ Warning: [CollectDependentSystemNode]: found symbols in the system headers: [:dispatch_data_t]
└ @ Clang.Generators ~/.julia/packages/Clang/uJQ2L/src/generator/passes.jl:95
ERROR: LoadError: There is no definition for dispatch_data_t's underlying type: [``] at /Users/tim/.julia/artifacts/fbb170fa64a06b66dd9a16aaa21bf12848042d9a/aarch64-apple-darwin20/sys-root/usr/include/dispatch/data.h:44:1
Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:35
 [2] resolve_dependency!(dag::ExprDAG, node::ExprNode{Clang.Generators.TypedefElaborated, CLTypedefDecl}, options::Dict{String, Any})
   @ Clang.Generators ~/.julia/packages/Clang/uJQ2L/src/generator/resolve_deps.jl:99
 [3] (::ResolveDependency)(dag::ExprDAG, options::Dict{String, Any})
   @ Clang.Generators ~/.julia/packages/Clang/uJQ2L/src/generator/passes.jl:286
 [4] build!(ctx::Context, stage::Clang.Generators.BuildStage)
   @ Clang.Generators ~/.julia/packages/Clang/uJQ2L/src/generator/context.jl:176
 [5] wrap(name::String, headers::String; defines::Vector{Any}, include_dirs::Vector{Any}, dependents::Bool)
   @ Main ~/Julia/pkg/Metal/res/wrap/wrap.jl:27
 [6] wrap
   @ ~/Julia/pkg/Metal/res/wrap/wrap.jl:13 [inlined]
 [7] main()
   @ Main ~/Julia/pkg/Metal/res/wrap/wrap.jl:59
 [8] top-level scope
   @ ~/Julia/pkg/Metal/res/wrap/wrap.jl:64
in expression starting at /Users/tim/Julia/pkg/Metal/res/wrap/wrap.jl:64

data.h:44:

DISPATCH_DATA_DECL(dispatch_data);

With the relevant macros for that:

#define DISPATCH_GLOBAL_OBJECT(type, object) ((OS_OBJECT_BRIDGE type)&(object))
#define DISPATCH_RETURNS_RETAINED OS_OBJECT_RETURNS_RETAINED
#elif defined(__cplusplus) && !defined(__DISPATCH_BUILDING_DISPATCH__)
/*
 * Dispatch objects are NOT C++ objects. Nevertheless, we can at least keep C++
 * aware of type compatibility.
 */
typedef struct dispatch_object_s {
private:
	dispatch_object_s();
	~dispatch_object_s();
	dispatch_object_s(const dispatch_object_s &);
	void operator=(const dispatch_object_s &);
} *dispatch_object_t;
#define DISPATCH_DECL(name) \
		typedef struct name##_s : public dispatch_object_s {} *name##_t
#define DISPATCH_DECL_SUBCLASS(name, base) \
		typedef struct name##_s : public base##_s {} *name##_t
#define DISPATCH_GLOBAL_OBJECT(type, object) (static_cast<type>(&(object)))
#define DISPATCH_RETURNS_RETAINED
#else /* Plain C */
typedef union {
	struct _os_object_s *_os_obj;
	struct dispatch_object_s *_do;
	struct dispatch_queue_s *_dq;
	struct dispatch_queue_attr_s *_dqa;
	struct dispatch_group_s *_dg;
	struct dispatch_source_s *_ds;
	struct dispatch_channel_s *_dch;
	struct dispatch_mach_s *_dm;
	struct dispatch_mach_msg_s *_dmsg;
	struct dispatch_semaphore_s *_dsema;
	struct dispatch_data_s *_ddata;
	struct dispatch_io_s *_dchannel;
} dispatch_object_t DISPATCH_TRANSPARENT_UNION;
#define DISPATCH_DECL(name) typedef struct name##_s *name##_t
#define DISPATCH_DECL_SUBCLASS(name, base) typedef base##_t name##_t
#define DISPATCH_GLOBAL_OBJECT(type, object) ((type)&(object))
#define DISPATCH_RETURNS_RETAINED
#endif

#if OS_OBJECT_SWIFT3 && OS_OBJECT_USE_OBJC
#define DISPATCH_SOURCE_TYPE_DECL(name) \
		DISPATCH_EXPORT struct dispatch_source_type_s \
				_dispatch_source_type_##name; \
		OS_OBJECT_DECL_PROTOCOL(dispatch_source_##name, <OS_dispatch_source>); \
		OS_OBJECT_CLASS_IMPLEMENTS_PROTOCOL( \
				dispatch_source, dispatch_source_##name)
#define DISPATCH_SOURCE_DECL(name) \
		DISPATCH_DECL(name); \
		OS_OBJECT_DECL_PROTOCOL(name, <NSObject>); \
		OS_OBJECT_CLASS_IMPLEMENTS_PROTOCOL(name, name)
#ifndef DISPATCH_DATA_DECL
#define DISPATCH_DATA_DECL(name) OS_OBJECT_DECL_SWIFT(name)
#endif // DISPATCH_DATA_DECL
#else
#define DISPATCH_SOURCE_DECL(name) \
		DISPATCH_DECL(name);
#define DISPATCH_DATA_DECL(name) DISPATCH_DECL(name)
#define DISPATCH_SOURCE_TYPE_DECL(name) \
		DISPATCH_EXPORT const struct dispatch_source_type_s \
		_dispatch_source_type_##name
#endif

Is this a known issue, or should I try to reduce the source code involved?