While we have 'ported' muslc it is worth pointing out that this does not mean the entire C library is usable. This is because all of the underlying unix syscalls are not implemented in any of our existing environments. For example, if you tried to call pthread_create, this would eventually result in attempting to call the clone syscall, which is not implemented and would fail.

A C++ standard library does not necessarily depend upon a C library, it just so happens that GCCs C++ library does. There are no good and maintained standalone C++ libraries that I am aware of. There use to be one by apache (http://stdcxx.apache.org/), but it has been discontinued.

The easiest approach is possibly to create a custom tool chain, and port the GCC C++ library that way. I know the people behind Genode did some of this (http://genode.org/download/tool-chain), although I'm not sure how much of the C++ standard library they actually support.

Adrian

On 18/06/15 01:58, Yuxin Ren wrote:
Hi Adrian,

Thank you for your explanation.
But I am still a little confused.
If a C++ program uses standard library, then both standard library C++ library and C library are needed, right?
And in sel4, you have ported a standard library C library (muslc), but you do not port any standard library C++ library to sel4. Is this correct?
I know some standard library C library, such as glibc or muslc, but I do not know any standard library C++ library.
Could you give me suggestion which C++ library may easy to port?

In additon, you said that you had some success with using your native gcc C++ libraries for compilation. Do you mean you link C++ program with Linux native C++ 
library first, and then link it to C library in sel4?

Thanks a lot!.
Yuxin

On Tue, Jun 16, 2015 at 8:42 PM, Adrian Danis <Adrian.Danis@nicta.com.au> wrote:
The seL4 kernel itself does not need anything for running C++ support. However, a version of the C++ standard library would need to be ported / implemented to a particular seL4 environment. If you would like to compile C++ code that does not use the standard library then this relatively easy and there is a trivial example in sel4test (see https://github.com/seL4/sel4test/blob/master/apps/sel4test-tests/src/tests/domains.cxx and https://github.com/seL4/sel4test/blob/master/apps/sel4test-tests/Makefile)

I had some success with using my native gcc C++ libraries for compilation, although it was a little fiddly to make work. The idea there is that since the C++ standard libraries depend upon the syscalls and other symbols defined in the C library you can just link against your native C++ libraries, and rely on the ported C library (in our case muslc) to implement the syscalls and make everything work.
I am not promoting this as a good idea or a way to build a reliable system, but might give you a bit of insight into what is required for a proper C++ port.

Adrian


On 17/06/15 08:32, Yuxin Ren wrote:
Hi,

Can I run C++ programs on sel4?
I am not familiar with programming language.
I do not know the relationship between the OS and the C++ language.
In order to run C++, does the OS need to provide some support or what user level library are needed?

Thanks a lot.
Yuxin


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