clang/docs/LibClang.rst - rust-lang/llvm-project - Git at Google

 .. role:: raw-html(raw)
     :format: html

 Libclang tutorial
 =================
 The C Interface to Clang provides a relatively small API that exposes facilities for parsing source code into an abstract syntax tree (AST), loading already-parsed ASTs, traversing the AST, associating physical source locations with elements within the AST, and other facilities that support Clang-based development tools.
 This C interface to Clang will never provide all of the information representation stored in Clang's C++ AST, nor should it: the intent is to maintain an API that is relatively stable from one release to the next, providing only the basic functionality needed to support development tools.
 The entire C interface of libclang is available in the file `Index.h`_

 Essential types overview
 -------------------------

 All types of libclang are prefixed with ``CX``

 CXIndex
 ~~~~~~~
 An Index that consists of a set of translation units that would typically be linked together into an executable or library.

 CXTranslationUnit
 ~~~~~~~~~~~~~~~~~
 A single translation unit, which resides in an index.

 CXCursor
 ~~~~~~~~
 A cursor representing a pointer to some element in the abstract syntax tree of a translation unit.


 Code example
 """"""""""""

 .. code-block:: cpp

   // file.cpp
   struct foo{
     int bar;
     int* bar_pointer;
   };

 .. code-block:: cpp

   #include <clang-c/Index.h>
   #include <iostream>

   int main(){
     CXIndex index = clang_createIndex(0, 0); //Create index
     CXTranslationUnit unit = clang_parseTranslationUnit(
       index,
       "file.cpp", nullptr, 0,
       nullptr, 0,
       CXTranslationUnit_None); //Parse "file.cpp"


     if (unit == nullptr){
       std::cerr << "Unable to parse translation unit. Quitting.\n";
       return 0;
     }
     CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit
   }

 Visiting elements of an AST
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The elements of an AST can be recursively visited with pre-order traversal with ``clang_visitChildren``.

 .. code-block:: cpp

   clang_visitChildren(
     cursor, //Root cursor
     [](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

       CXString current_display_name = clang_getCursorDisplayName(current_cursor);
       //Allocate a CXString representing the name of the current cursor

       std::cout << "Visiting element " << clang_getCString(current_display_name) << "\n";
       //Print the char* value of current_display_name

       clang_disposeString(current_display_name);
       //Since clang_getCursorDisplayName allocates a new CXString, it must be freed. This applies
       //to all functions returning a CXString

       return CXChildVisit_Recurse;


     }, //CXCursorVisitor: a function pointer
     nullptr //client_data
     );

 The return value of ``CXCursorVisitor``, the callable argument of ``clang_visitChildren``, can return one of the three:

 #. ``CXChildVisit_Break``: Terminates the cursor traversal

 #. ``CXChildVisit_Continue``: Continues the cursor traversal with the next sibling of the cursor just visited, without visiting its children.

 #. ``CXChildVisit_Recurse``: Recursively traverse the children of this cursor, using the same visitor and client data

 The expected output of that program is

 .. code-block::

   Visiting element foo
   Visiting element bar
   Visiting element bar_pointer


 Extracting information from a Cursor
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 .. The following functions take a ``CXCursor`` as an argument and return associated information.


 Extracting the Cursor kind
 """"""""""""""""""""""""""

 ``CXCursorKind clang_getCursorKind(CXCursor)`` Describes the kind of entity that a cursor refers to. Example values:

 - ``CXCursor_StructDecl``: A C or C++ struct.
 - ``CXCursor_FieldDecl``: A field in a struct, union, or C++ class.
 - ``CXCursor_CallExpr``: An expression that calls a function.


 Extracting the Cursor type
 """"""""""""""""""""""""""
 ``CXType clang_getCursorType(CXCursor)``: Retrieve the type of a CXCursor (if any).

 A ``CXType`` represents a complete C++ type, including qualifiers and pointers. It has a member field ``CXTypeKind kind`` and additional opaque data.

 Example values for ``CXTypeKind kind``

 - ``CXType_Invalid``: Represents an invalid type (e.g., where no type is available)
 - ``CXType_Pointer``: A pointer to another type
 - ``CXType_Int``: Regular ``int``
 - ``CXType_Elaborated``: Represents a type that was referred to using an elaborated type keyword e.g. struct S, or via a qualified name, e.g., N::M::type, or both.

 Any ``CXTypeKind`` can be converted to a ``CXString`` using ``clang_getTypeKindSpelling(CXTypeKind)``.

 A ``CXType`` holds additional necessary opaque type info, such as:

 - Which struct was referred to?
 - What type is the pointer pointing to?
 - Qualifiers (e.g. ``const``, ``volatile``)?

 Qualifiers of a ``CXType`` can be queried with:

 - ``clang_isConstQualifiedType(CXType)`` to check for ``const``
 - ``clang_isRestrictQualifiedType(CXType)`` to check for ``restrict``
 - ``clang_isVolatileQualifiedType(CXType)`` to check for ``volatile``

 Code example
 """"""""""""
 .. code-block:: cpp

   //structs.cpp
   struct A{
     int value;
   };
   struct B{
     int value;
     A struct_value;
   };

 .. code-block:: cpp

   #include <clang-c/Index.h>
   #include <iostream>

   int main(){
     CXIndex index = clang_createIndex(0, 0); //Create index
     CXTranslationUnit unit = clang_parseTranslationUnit(
       index,
       "structs.cpp", nullptr, 0,
       nullptr, 0,
       CXTranslationUnit_None); //Parse "structs.cpp"

     if (unit == nullptr){
       std::cerr << "Unable to parse translation unit. Quitting.\n";
       return 0;
     }
     CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit

     clang_visitChildren(
     cursor,
     [](CXCursor current_cursor, CXCursor parent, CXClientData client_data){
       CXType cursor_type = clang_getCursorType(current_cursor);

       CXString type_kind_spelling = clang_getTypeKindSpelling(cursor_type.kind);
       std::cout << "Type Kind: " << clang_getCString(type_kind_spelling);
       clang_disposeString(type_kind_spelling);

       if(cursor_type.kind == CXType_Pointer ||                     // If cursor_type is a pointer
         cursor_type.kind == CXType_LValueReference ||              // or an LValue Reference (&)
         cursor_type.kind == CXType_RValueReference){               // or an RValue Reference (&&),
         CXType pointed_to_type = clang_getPointeeType(cursor_type);// retrieve the pointed-to type

         CXString pointed_to_type_spelling = clang_getTypeSpelling(pointed_to_type);     // Spell out the entire
         std::cout << "pointing to type: " << clang_getCString(pointed_to_type_spelling);// pointed-to type
         clang_disposeString(pointed_to_type_spelling);
       }
       else if(cursor_type.kind == CXType_Record){
         CXString type_spelling = clang_getTypeSpelling(cursor_type);
         std::cout <<  ", namely " << clang_getCString(type_spelling);
         clang_disposeString(type_spelling);
       }
       std::cout << "\n";
       return CXChildVisit_Recurse;
     },
     nullptr
     );

 The expected output of program is:

 .. code-block::

   Type Kind: Record, namely A
   Type Kind: Int
   Type Kind: Record, namely B
   Type Kind: Int
   Type Kind: Record, namely A
   Type Kind: Record, namely A


 Reiterating the difference between ``CXType`` and ``CXTypeKind``: For an example

 .. code-block:: cpp

    const char* __restrict__ variable;

 - Type Kind will be: ``CXType_Pointer`` spelled ``"Pointer"``
 - Type will be a complex ``CXType`` structure, spelled ``"const char* __restrict__``

 Retrieving source locations
 """""""""""""""""""""""""""

 ``CXSourceRange clang_getCursorExtent(CXCursor)`` returns a ``CXSourceRange``, representing a half-open range in the source code.

 Use ``clang_getRangeStart(CXSourceRange)`` and ``clang_getRangeEnd(CXSourceRange)`` to retrieve the starting and end ``CXSourceLocation`` from a source range, respectively.

 Given a ``CXSourceLocation``, use ``clang_getExpansionLocation`` to retrieve file, line and column of a source location.

 Code example
 """"""""""""
 .. code-block:: cpp

   // Again, file.cpp
   struct foo{
     int bar;
     int* bar_pointer;
   };
 .. code-block:: cpp

   clang_visitChildren(
     cursor,
     [](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

       CXType cursor_type = clang_getCursorType(current_cursor);
       CXString cursor_spelling = clang_getCursorSpelling(current_cursor);
       CXSourceRange cursor_range = clang_getCursorExtent(current_cursor);
       std::cout << "Cursor " << clang_getCString(cursor_spelling);

       CXFile file;
       unsigned start_line, start_column, start_offset;
       unsigned end_line, end_column, end_offset;

       clang_getExpansionLocation(clang_getRangeStart(cursor_range), &file, &start_line, &start_column, &start_offset);
       clang_getExpansionLocation(clang_getRangeEnd  (cursor_range), &file, &end_line  , &end_column  , &end_offset);
       std::cout << " spanning lines " << start_line << " to " << end_line;
       clang_disposeString(cursor_spelling);

       std::cout << "\n";
       return CXChildVisit_Recurse;
     },
     nullptr
   );

 The expected output of this program is:

 .. code-block::

   Cursor foo spanning lines 2 to 5
   Cursor bar spanning lines 3 to 3
   Cursor bar_pointer spanning lines 4 to 4

 Complete example code
 ~~~~~~~~~~~~~~~~~~~~~

 .. code-block:: cpp

   #include <clang-c/Index.h>
   #include <iostream>

   int main(){
     CXIndex index = clang_createIndex(0, 0); //Create index
     CXTranslationUnit unit = clang_parseTranslationUnit(
       index,
       "file.cpp", nullptr, 0,
       nullptr, 0,
       CXTranslationUnit_None); //Parse "file.cpp"

     if (unit == nullptr){
       std::cerr << "Unable to parse translation unit. Quitting.\n";
       return 0;
     }
     CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit


     clang_visitChildren(
     cursor,
     [](CXCursor current_cursor, CXCursor parent, CXClientData client_data){
       CXType cursor_type = clang_getCursorType(current_cursor);

       CXString type_kind_spelling = clang_getTypeKindSpelling(cursor_type.kind);
       std::cout << "TypeKind: " << clang_getCString(type_kind_spelling);
       clang_disposeString(type_kind_spelling);

       if(cursor_type.kind == CXType_Pointer ||                     // If cursor_type is a pointer
         cursor_type.kind == CXType_LValueReference ||              // or an LValue Reference (&)
         cursor_type.kind == CXType_RValueReference){               // or an RValue Reference (&&),
         CXType pointed_to_type = clang_getPointeeType(cursor_type);// retrieve the pointed-to type

         CXString pointed_to_type_spelling = clang_getTypeSpelling(pointed_to_type);     // Spell out the entire
         std::cout << "pointing to type: " << clang_getCString(pointed_to_type_spelling);// pointed-to type
         clang_disposeString(pointed_to_type_spelling);
       }
       else if(cursor_type.kind == CXType_Record){
         CXString type_spelling = clang_getTypeSpelling(cursor_type);
         std::cout <<  ", namely " << clang_getCString(type_spelling);
         clang_disposeString(type_spelling);
       }
       std::cout << "\n";
       return CXChildVisit_Recurse;
     },
     nullptr
     );


     clang_visitChildren(
     cursor,
     [](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

       CXType cursor_type = clang_getCursorType(current_cursor);
       CXString cursor_spelling = clang_getCursorSpelling(current_cursor);
       CXSourceRange cursor_range = clang_getCursorExtent(current_cursor);
       std::cout << "Cursor " << clang_getCString(cursor_spelling);

       CXFile file;
       unsigned start_line, start_column, start_offset;
       unsigned end_line, end_column, end_offset;

       clang_getExpansionLocation(clang_getRangeStart(cursor_range), &file, &start_line, &start_column, &start_offset);
       clang_getExpansionLocation(clang_getRangeEnd  (cursor_range), &file, &end_line  , &end_column  , &end_offset);
       std::cout << " spanning lines " << start_line << " to " << end_line;
       clang_disposeString(cursor_spelling);

       std::cout << "\n";
       return CXChildVisit_Recurse;
     },
     nullptr
     );
   }


 .. _Index.h: https://github.com/llvm/llvm-project/blob/main/clang/include/clang-c/Index.h
	.. role:: raw-html(raw)
	:format: html

	Libclang tutorial
	=================
	The C Interface to Clang provides a relatively small API that exposes facilities for parsing source code into an abstract syntax tree (AST), loading already-parsed ASTs, traversing the AST, associating physical source locations with elements within the AST, and other facilities that support Clang-based development tools.
	This C interface to Clang will never provide all of the information representation stored in Clang's C++ AST, nor should it: the intent is to maintain an API that is relatively stable from one release to the next, providing only the basic functionality needed to support development tools.
	The entire C interface of libclang is available in the file `Index.h`_

	Essential types overview
	-------------------------

	All types of libclang are prefixed with ``CX``

	CXIndex
	~~~~~~~
	An Index that consists of a set of translation units that would typically be linked together into an executable or library.

	CXTranslationUnit
	~~~~~~~~~~~~~~~~~
	A single translation unit, which resides in an index.

	CXCursor
	~~~~~~~~
	A cursor representing a pointer to some element in the abstract syntax tree of a translation unit.


	Code example
	""""""""""""

	.. code-block:: cpp

	// file.cpp
	struct foo{
	int bar;
	int* bar_pointer;
	};

	.. code-block:: cpp

	#include <clang-c/Index.h>
	#include <iostream>

	int main(){
	CXIndex index = clang_createIndex(0, 0); //Create index
	CXTranslationUnit unit = clang_parseTranslationUnit(
	index,
	"file.cpp", nullptr, 0,
	nullptr, 0,
	CXTranslationUnit_None); //Parse "file.cpp"


	if (unit == nullptr){
	std::cerr << "Unable to parse translation unit. Quitting.\n";
	return 0;
	}
	CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit
	}

	Visiting elements of an AST
	~~~~~~~~~~~~~~~~~~~~~~~~~~~
	The elements of an AST can be recursively visited with pre-order traversal with ``clang_visitChildren``.

	.. code-block:: cpp

	clang_visitChildren(
	cursor, //Root cursor
	[](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

	CXString current_display_name = clang_getCursorDisplayName(current_cursor);
	//Allocate a CXString representing the name of the current cursor

	std::cout << "Visiting element " << clang_getCString(current_display_name) << "\n";
	//Print the char* value of current_display_name

	clang_disposeString(current_display_name);
	//Since clang_getCursorDisplayName allocates a new CXString, it must be freed. This applies
	//to all functions returning a CXString

	return CXChildVisit_Recurse;


	}, //CXCursorVisitor: a function pointer
	nullptr //client_data
	);

	The return value of ``CXCursorVisitor``, the callable argument of ``clang_visitChildren``, can return one of the three:

	#. ``CXChildVisit_Break``: Terminates the cursor traversal

	#. ``CXChildVisit_Continue``: Continues the cursor traversal with the next sibling of the cursor just visited, without visiting its children.

	#. ``CXChildVisit_Recurse``: Recursively traverse the children of this cursor, using the same visitor and client data

	The expected output of that program is

	.. code-block::

	Visiting element foo
	Visiting element bar
	Visiting element bar_pointer


	Extracting information from a Cursor
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	.. The following functions take a ``CXCursor`` as an argument and return associated information.



	Extracting the Cursor kind
	""""""""""""""""""""""""""

	``CXCursorKind clang_getCursorKind(CXCursor)`` Describes the kind of entity that a cursor refers to. Example values:

	- ``CXCursor_StructDecl``: A C or C++ struct.
	- ``CXCursor_FieldDecl``: A field in a struct, union, or C++ class.
	- ``CXCursor_CallExpr``: An expression that calls a function.


	Extracting the Cursor type
	""""""""""""""""""""""""""
	``CXType clang_getCursorType(CXCursor)``: Retrieve the type of a CXCursor (if any).

	A ``CXType`` represents a complete C++ type, including qualifiers and pointers. It has a member field ``CXTypeKind kind`` and additional opaque data.

	Example values for ``CXTypeKind kind``

	- ``CXType_Invalid``: Represents an invalid type (e.g., where no type is available)
	- ``CXType_Pointer``: A pointer to another type
	- ``CXType_Int``: Regular ``int``
	- ``CXType_Elaborated``: Represents a type that was referred to using an elaborated type keyword e.g. struct S, or via a qualified name, e.g., N::M::type, or both.

	Any ``CXTypeKind`` can be converted to a ``CXString`` using ``clang_getTypeKindSpelling(CXTypeKind)``.

	A ``CXType`` holds additional necessary opaque type info, such as:

	- Which struct was referred to?
	- What type is the pointer pointing to?
	- Qualifiers (e.g. ``const``, ``volatile``)?

	Qualifiers of a ``CXType`` can be queried with:

	- ``clang_isConstQualifiedType(CXType)`` to check for ``const``
	- ``clang_isRestrictQualifiedType(CXType)`` to check for ``restrict``
	- ``clang_isVolatileQualifiedType(CXType)`` to check for ``volatile``

	Code example
	""""""""""""
	.. code-block:: cpp

	//structs.cpp
	struct A{
	int value;
	};
	struct B{
	int value;
	A struct_value;
	};

	.. code-block:: cpp

	#include <clang-c/Index.h>
	#include <iostream>

	int main(){
	CXIndex index = clang_createIndex(0, 0); //Create index
	CXTranslationUnit unit = clang_parseTranslationUnit(
	index,
	"structs.cpp", nullptr, 0,
	nullptr, 0,
	CXTranslationUnit_None); //Parse "structs.cpp"

	if (unit == nullptr){
	std::cerr << "Unable to parse translation unit. Quitting.\n";
	return 0;
	}
	CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit

	clang_visitChildren(
	cursor,
	[](CXCursor current_cursor, CXCursor parent, CXClientData client_data){
	CXType cursor_type = clang_getCursorType(current_cursor);

	CXString type_kind_spelling = clang_getTypeKindSpelling(cursor_type.kind);
	std::cout << "Type Kind: " << clang_getCString(type_kind_spelling);
	clang_disposeString(type_kind_spelling);

	if(cursor_type.kind == CXType_Pointer \|\| // If cursor_type is a pointer
	cursor_type.kind == CXType_LValueReference \|\| // or an LValue Reference (&)
	cursor_type.kind == CXType_RValueReference){ // or an RValue Reference (&&),
	CXType pointed_to_type = clang_getPointeeType(cursor_type);// retrieve the pointed-to type

	CXString pointed_to_type_spelling = clang_getTypeSpelling(pointed_to_type); // Spell out the entire
	std::cout << "pointing to type: " << clang_getCString(pointed_to_type_spelling);// pointed-to type
	clang_disposeString(pointed_to_type_spelling);
	}
	else if(cursor_type.kind == CXType_Record){
	CXString type_spelling = clang_getTypeSpelling(cursor_type);
	std::cout << ", namely " << clang_getCString(type_spelling);
	clang_disposeString(type_spelling);
	}
	std::cout << "\n";
	return CXChildVisit_Recurse;
	},
	nullptr
	);

	The expected output of program is:

	.. code-block::

	Type Kind: Record, namely A
	Type Kind: Int
	Type Kind: Record, namely B
	Type Kind: Int
	Type Kind: Record, namely A
	Type Kind: Record, namely A


	Reiterating the difference between ``CXType`` and ``CXTypeKind``: For an example

	.. code-block:: cpp

	const char* __restrict__ variable;

	- Type Kind will be: ``CXType_Pointer`` spelled ``"Pointer"``
	- Type will be a complex ``CXType`` structure, spelled ``"const char* __restrict__``

	Retrieving source locations
	"""""""""""""""""""""""""""

	``CXSourceRange clang_getCursorExtent(CXCursor)`` returns a ``CXSourceRange``, representing a half-open range in the source code.

	Use ``clang_getRangeStart(CXSourceRange)`` and ``clang_getRangeEnd(CXSourceRange)`` to retrieve the starting and end ``CXSourceLocation`` from a source range, respectively.

	Given a ``CXSourceLocation``, use ``clang_getExpansionLocation`` to retrieve file, line and column of a source location.

	Code example
	""""""""""""
	.. code-block:: cpp

	// Again, file.cpp
	struct foo{
	int bar;
	int* bar_pointer;
	};
	.. code-block:: cpp

	clang_visitChildren(
	cursor,
	[](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

	CXType cursor_type = clang_getCursorType(current_cursor);
	CXString cursor_spelling = clang_getCursorSpelling(current_cursor);
	CXSourceRange cursor_range = clang_getCursorExtent(current_cursor);
	std::cout << "Cursor " << clang_getCString(cursor_spelling);

	CXFile file;
	unsigned start_line, start_column, start_offset;
	unsigned end_line, end_column, end_offset;

	clang_getExpansionLocation(clang_getRangeStart(cursor_range), &file, &start_line, &start_column, &start_offset);
	clang_getExpansionLocation(clang_getRangeEnd (cursor_range), &file, &end_line , &end_column , &end_offset);
	std::cout << " spanning lines " << start_line << " to " << end_line;
	clang_disposeString(cursor_spelling);

	std::cout << "\n";
	return CXChildVisit_Recurse;
	},
	nullptr
	);

	The expected output of this program is:

	.. code-block::

	Cursor foo spanning lines 2 to 5
	Cursor bar spanning lines 3 to 3
	Cursor bar_pointer spanning lines 4 to 4

	Complete example code
	~~~~~~~~~~~~~~~~~~~~~

	.. code-block:: cpp

	#include <clang-c/Index.h>
	#include <iostream>

	int main(){
	CXIndex index = clang_createIndex(0, 0); //Create index
	CXTranslationUnit unit = clang_parseTranslationUnit(
	index,
	"file.cpp", nullptr, 0,
	nullptr, 0,
	CXTranslationUnit_None); //Parse "file.cpp"

	if (unit == nullptr){
	std::cerr << "Unable to parse translation unit. Quitting.\n";
	return 0;
	}
	CXCursor cursor = clang_getTranslationUnitCursor(unit); //Obtain a cursor at the root of the translation unit


	clang_visitChildren(
	cursor,
	[](CXCursor current_cursor, CXCursor parent, CXClientData client_data){
	CXType cursor_type = clang_getCursorType(current_cursor);

	CXString type_kind_spelling = clang_getTypeKindSpelling(cursor_type.kind);
	std::cout << "TypeKind: " << clang_getCString(type_kind_spelling);
	clang_disposeString(type_kind_spelling);

	if(cursor_type.kind == CXType_Pointer \|\| // If cursor_type is a pointer
	cursor_type.kind == CXType_LValueReference \|\| // or an LValue Reference (&)
	cursor_type.kind == CXType_RValueReference){ // or an RValue Reference (&&),
	CXType pointed_to_type = clang_getPointeeType(cursor_type);// retrieve the pointed-to type

	CXString pointed_to_type_spelling = clang_getTypeSpelling(pointed_to_type); // Spell out the entire
	std::cout << "pointing to type: " << clang_getCString(pointed_to_type_spelling);// pointed-to type
	clang_disposeString(pointed_to_type_spelling);
	}
	else if(cursor_type.kind == CXType_Record){
	CXString type_spelling = clang_getTypeSpelling(cursor_type);
	std::cout << ", namely " << clang_getCString(type_spelling);
	clang_disposeString(type_spelling);
	}
	std::cout << "\n";
	return CXChildVisit_Recurse;
	},
	nullptr
	);


	clang_visitChildren(
	cursor,
	[](CXCursor current_cursor, CXCursor parent, CXClientData client_data){

	CXType cursor_type = clang_getCursorType(current_cursor);
	CXString cursor_spelling = clang_getCursorSpelling(current_cursor);
	CXSourceRange cursor_range = clang_getCursorExtent(current_cursor);
	std::cout << "Cursor " << clang_getCString(cursor_spelling);

	CXFile file;
	unsigned start_line, start_column, start_offset;
	unsigned end_line, end_column, end_offset;

	clang_getExpansionLocation(clang_getRangeStart(cursor_range), &file, &start_line, &start_column, &start_offset);
	clang_getExpansionLocation(clang_getRangeEnd (cursor_range), &file, &end_line , &end_column , &end_offset);
	std::cout << " spanning lines " << start_line << " to " << end_line;
	clang_disposeString(cursor_spelling);

	std::cout << "\n";
	return CXChildVisit_Recurse;
	},
	nullptr
	);
	}


	.. _Index.h: https://github.com/llvm/llvm-project/blob/main/clang/include/clang-c/Index.h