Before I start building one myself;
Is there a wrapper for C or C++ which does the same thing as SVNKit?
There is an API provided in C - see the Subversion Documentation
Related
Hello I have developed a package using Rcpp and I would like to use within this package some C code from another package (for reference the package in question is rkdb and the function is from_any_k_object)
I would like to know if this is possible (I think it is as I've seen quite a few question concerning using C code in C++ - not from a package though)
If it is I would be glad to get some examples.
EDIT: I can add 2 minimal packages (using C/C++ resp.) with a unique function for minimal example
I have written a c++ program by using UIAutomation on windows. The libraries I have used are windows.h and Uiautomation.h. It works well. However, I want to convert the program to C program. (There is no classes). When I try to do it, I have taken an error which is error: unknown type name 'IUIAutomationElement'. Even file included libraries are enough in the cpp program, why the C version does not run?
Thank you...
After a quick look into Microsoft doc., it is clear that IUIAutomationElement element is a C++ class and cannot be directly used from a C program. Your own code can be plain C, but you will have to use an wrapper module in C++ that declares some extern "C" functions. They will be callable from C and will be able to use IUIAutomationElement.
Let say I have a C++ DLL. AFAIK, there is no widely-adopted ABI standard for C++, therefore to make sure it works and does not depend on the compiler of the target application I would need to wrap my library in a C interface.
Are there any tools that can automatically generate such interface? Would also be nice if they could generate wrappers around C interface to look as if they are original C++ objects, e.g.
Foo* f = new Foo(); // FooWrapper* fw = Foo_create();
f->bar("test"); // Foo_bar(fw, "test")
translates into C functions that are invoked in my library using generated C ABI. I understand that C++ is fairly complicated language and not everything can be easily wrapped in a C interface, but I was wondering if there are any such solutions that even support a subset of the C++ language (maybe with the help of some manually written IDL/XML files)?
there is no widely-adopted ABI standard for C++
I'm pretty sure that is a bit exaggerated - there aren't THAT many different compilers available for any given platform, so it would probably be easier to just produce a DLL for each vendor (e.g. Microsoft, GCC on Windows, GCC on Linux, Sun and GCC for Solaris, GCC for MacOS - CLANG is compatible with GCC as far as I know).
To add a C layer interface basically means that the interface layer must not:
1. Use any objects of that require special copy/assignment/construction behaviour.
2. Use any "throw" exceptions.
3. Use virtual functions.
across that interface.
It is my opinion that it's easier to "fix" the problems caused by "lack of ABI" than it is to make a good interface suitable for C++ use with a C interface in the middle of it.
If you want a way to make C++ code callable from other compilers/standard libraries, you can use cppcomponents from https://github.com/jbandela/cppcomponents. Full disclosure - I am the author of the library.
Here is a simple hello world example
First make a file called library.h
In this file you will define the Component
#include <cppcomponents/cppcomponents.hpp>
struct IPerson
:public cppcomponents::define_interface<cppcomponents::uuid<0xc618fd04,0xaa62,0x46e0,0xaeb8,0x6605eb4a1e64>>
{
std::string SayHello();
CPPCOMPONENTS_CONSTRUCT(IPerson,SayHello);
};
inline std::string PersonId(){return "library!Person";}
typedef cppcomponents::runtime_class<PersonId,cppcomponents::object_interfaces<IPerson>> Person_t;
typedef cppcomponents::use_runtime_class<Person_t> Person;
Next create library.cpp
In this file you will implement the interface and component
#include "library.h"
struct PersonImplementation:cppcomponents::implement_runtime_class<PersonImplementation,Person_t>
{
std::string SayHello(){return "Hello World\n";}
};
CPPCOMPONENTS_DEFINE_FACTORY(PersonImplementation);
Finally here is you main program (call it example1.cpp) that uses your implementation
#include "library.h"
#include <iostream>
int main(){
Person p;
std::cout << p.SayHello();
}
To build the program you will need to download cppcomponents (just clone from the git link above). It is a header only library and needs only a c++11 compiler.
Here is how you would build it on Windows
cl /EHsc example1.cpp /I pathtocppcomponents
g++ -std=c++11 library.cpp -o library.dll -shared -I pathtocppcomponents
where pathocppcomponents is the directory of cppcomponents.
I am assuming you have cl and g++ in your path.
To run the program, make sure library.dll is in the same directory as example1.exe and run example1.exe
This library requires fairly compliant c++11 support, so it needs MSVC 2013 Preview, and at least g++ 4.7. This library works on both Windows and Linux.
As far as I know the answer is no and you are supposed to handle this by yourself with a little bit of "hacking" and modifications, for example your t variable which is an std::string can possibly be "externed" to a C interface by t.c_str() because c_str returns a const char * which is a type that C understands without any problem at all.
I personally don't find C++ complicated, I can't see that "ABI issue" either, I mean nothing is perfect but you are externalizing to C your entire code base to "solve" this issue ? Just use C in the first place, also C it's no easy language to deal with either, for example in C there is not even the notion of "string", and problems that are trivial to solve in C++ while keeping everything type-safe, are really challenging in C if you want to meet the same goal.
I think that you are going a little bit too far with this, and you are complicating things, as it is now you have 3 + 1 main options on the most popular platforms :
libsupc++
libcxxrt
libc++abi
plus the whetever ABI is for the MSVC of your choice ( aka "only god knows")
for me, on linux, libsupc++ works very well, I'm following the libc++abi project and I don't see any big problem either, the only real problem with this is that llvm is basically an Apple oriented project for now, so there isn't that real and good support for the other platforms, but libc++abi compiles and works quite well on linux too ( although it's basically useless and pointless, on linux there is libsupc++ already.) .
I also would never ever use MSVC under Windows, in my opinion it's better to stick with a GCC-like compiler such as mingw, you got bleeding edge features, and you can simplify your codebase and your building phase a lot.
I want to use LEAP Motion in D.
Therefore It doesn't have C library and It has only C++ library.
I tried SWIG 2.0.9 below command.
swig -c++ -d -d2 leap.i
This command output Leap.d, Leap_im.d, Leap_wrap.cxx, Leap_wrap.h.
However, I don't know how to use to wrapper in D and I can't find how to use the wrapper.
Link error displays to use it intact.
How use these wrapper in D2?
And can I use without Leap.cpp (source of Leap.dll)?
Update:
Thanks two answers. and sorry for reply late because of busy.
Say first conclusion I could build Leap sample code on Win64 by following the steps below.
Output wrappers by above command.
Create x64 DLL with VC2010 from Leap_wrap.cxx, Leap_wrap.h, and import Leap.lib(x64).
Compile Leap.d and Leap_im.d with dmd -c.
Build LeapTest.d with Leap.obj and Leap_im.obj
all command is below.
swig -c++ -d -d2 leap.i
dmd -c Leap.d Leap_im.d -m64
dmd LeapTest.d Leap.obj Leap_im.obj -m64
execute LeapTest.exe (require x64 Leap.dll and Leap_wrap.dll)
I could run Leap Program.
But program crach onFrame event callback.
I'll try again on x86 and investigate the causes.
Few helpful links (some information may be outdated):
http://klickverbot.at/blog/2010/11/announcing-d-support-in-swig/
http://www.swig.org/Doc2.0/D.html
http://www.swig.org/tutorial.html
I have never used SWIG personally but my guess based on general knowledge about SWIG:
Leap_wrap.cxx is C++ source file that wraps calls to C++ functions from target library in extern(C) calls
Leap_wrap.h is header file with all extern(C) wrappers listed
Leap_im.d is D module based on Leap_wrap.h with same extern(C) function listed
Leap.d is D module that uses Leap_im.d as an implementation and reproduces API similar to original C++ one.
So in your D code you want to import Leap.d module. Than compile Leap_wrap.cxx to an object file with your C++ compiler and provide D object files, Leap_wrap.o and target library at linking stage. That should do the trick.
P.S. Leap.cpp source should not be needed. All stuff links directly from Leap_wrap.cxx to target library binary.
Go to IRC, either FreeNode, or OFTC, channel #D. In order to help you, we have to see what is in those files. My first guess is that you have to compile both D files, and the C++ file into object files, and link them together. I suppose SWIG is going to flatten the C++ API into bunch of C functions, and that is probably what Leap_wrap.cxx does.
If the LEAP API is not complex (ie. just bunch of simple C++ classes), it may be possible to directly interface with it. Read more about it here: http://dlang.org/cpp_interface.html .
I am trying to setup a mqueue in win32 env, but need pthread win32 lib, http://sourceware.org/pthreads-win32/. Any one knows how to link it to my VS project?
Thanks
You need to link to one of the Visual C++ .lib files, which are named differently depending on what exception handling you wish in the library. See the FAQ here, items 2. and 3. for further details.
In general:
pthread[VG]{SE,CE,C}.dll
pthread[VG]{SE,CE,C}.lib
where:
[VG] indicates the compiler
V - MS VC
G - GNU C
{SE,CE,C} indicates the exception handling scheme
SE - Structured EH
CE - C++ EH
C - no exceptions - uses setjmp/longjmp
For example:
pthreadVSE.dll (MSVC/SEH)
pthreadGCE.dll (GNUC/C++ EH)
pthreadGC.dll (GNUC/not dependent on exceptions)