digitalmars.D - how to get typeid of extern(C++) classes?
- Timothee Cour (13/13) Feb 15 2018 is there a way to get typeid of extern(C++) classes (eg for ones in
- timotheecour (5/8) Feb 16 2018 as a workaround, could the compiler insert (eg, depending on a
- Steven Schveighoffer (7/24) Feb 16 2018 typeid always returns a D TypeInfo object, which is a D-specific animal.
- Meta (4/5) Feb 16 2018 It's been awhile since I've written any C++ code, but as I
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Jonathan M Davis
(6/11)
Feb 16 2018
I think that all that's required is #including
. Certainly, I'... - Stefan Koch (3/12) Feb 16 2018 look at the asttypename.d in the dmd source.
is there a way to get typeid of extern(C++) classes (eg for ones in dmd/astbase.d but not limited to that) ? C++ exposes it via typeid so in theory all the info is there ; I would need it at least for debugging (eg if RTTI is not enabled for all compilers or in release mode that's fine so long there's a documented way to get it for debugging) a lot of extern(C++) classes in dmd use hacks like enum values to get their type but it's unreliable and doesn't work for all AST classes. at least having a way to expose typeid(instance).name() would be a start also, that could be used to fix the bug I posted here: https://forum.dlang.org/post/mailman.3138.1517949584.9493.digitalmars-d puremagic.com cast overly permissive with extern(C++ ) classes; ( ie that `cast(A) b` doesn't care that b is of dynamic type A)
Feb 15 2018
On Friday, 16 February 2018 at 00:42:02 UTC, Timothee Cour wrote:is there a way to get typeid of extern(C++) classes (eg for ones in dmd/astbase.d but not limited to that) ?as a workaround, could the compiler insert (eg, depending on a version(insert_typeid)) a virtual method in each extern(C++) class eg: `const(char)* __typeid()` ?
Feb 16 2018
On 2/15/18 7:42 PM, Timothee Cour wrote:is there a way to get typeid of extern(C++) classes (eg for ones in dmd/astbase.d but not limited to that) ? C++ exposes it via typeid so in theory all the info is there ; I would need it at least for debugging (eg if RTTI is not enabled for all compilers or in release mode that's fine so long there's a documented way to get it for debugging) a lot of extern(C++) classes in dmd use hacks like enum values to get their type but it's unreliable and doesn't work for all AST classes. at least having a way to expose typeid(instance).name() would be a start also, that could be used to fix the bug I posted here: https://forum.dlang.org/post/mailman.3138.1517949584.9493.digitalmars-d puremagic.com cast overly permissive with extern(C++ ) classes; ( ie that `cast(A) b` doesn't care that b is of dynamic type A)typeid always returns a D TypeInfo object, which is a D-specific animal. I don't think we can do this for C++ classes. For D classes in particular, the typeid is a runtime type, gleaned from the embedded vtable. For structs, it is a compile-time defined reference. Neither of these things would exist for C++ classes. -Steve
Feb 16 2018
On Friday, 16 February 2018 at 00:42:02 UTC, Timothee Cour wrote:C++ exposes it via typeid so in theory all the info is there ;It's been awhile since I've written any C++ code, but as I remember it, this type of type info is not available unless you enable it with a (C++) compiler switch.
Feb 16 2018
On Saturday, February 17, 2018 00:23:01 Meta via Digitalmars-d wrote:On Friday, 16 February 2018 at 00:42:02 UTC, Timothee Cour wrote:I think that all that's required is #including <typeinfo>. Certainly, I've never used a compiler switch to get at it, but I have no clue what <typeinfo> really does to make things work beyond making certain symbols available. So, I don't know how easy it is to make it work from D code. - Jonathan M DavisC++ exposes it via typeid so in theory all the info is there ;It's been awhile since I've written any C++ code, but as I remember it, this type of type info is not available unless you enable it with a (C++) compiler switch.
Feb 16 2018
On Friday, 16 February 2018 at 00:42:02 UTC, Timothee Cour wrote:is there a way to get typeid of extern(C++) classes (eg for ones in dmd/astbase.d but not limited to that) ? C++ exposes it via typeid so in theory all the info is there ; I would need it at least for debugging (eg if RTTI is not enabled for all compilers or in release mode that's fine so long there's a documented way to get it for debugging) [...]look at the asttypename.d in the dmd source. it can give you a sting which represnts the ast-type-name.
Feb 16 2018