GO instead of C/C++ with cgo

Question

Is it possible to replace C and C++ with Go + cgo and interface frameworks such as Qt or DirectX with Go?

Any potential pitfalls I should be aware of?

UPDATE:

I see that my question was not precise enough. Of course I expected problems with Go concepts that aren't available in C/C++ e.g. goroutines. What I really wanted to know was if you could use Go to replace standard C++ functionality. I hope I can convey my idea: I thought of Go as a "scripting language" to leverage C/C++ libraries with a new language.

I'd like to know:

• Can you register Go methods as C/C++ callbacks ?
• Can I supply Go variables as parameters to C/C++ functions ?
• Are their pointers compatible ? Go runs on a native Vm, so I guessed there might be an abstraction layer over the memory that invalidates C/C++ pointers

Have you ever used cgo or know about its abilities ?

Answer 1

Go has a simple interface to C libraries: cgo. It has no support for C++ (classes, name mangling). An alternative to cgo is Swig.

Can you register Go methods as C/C++ callbacks ?

It is possible to call Go functions (not methods) from C. A simple example can be found here.

It is hard to understand what the limitations of calling C from Go are.

Cgo has currently no support for generating standalone Go libraries (.a or .so) for use from C code. Go programs are able to use C libraries, but C programs are unable to use Go libraries.

Can I supply Go variables as parameters to C/C++ functions ?

Yes. The ability to pass Go values to C (cgo) is restricted by the Go type system. For example, the C type int is accessible from Go as C.int, so the programmer has to use an explicit type conversion even when passing integers (this verbosity is intentional).

Go source codes interfacing to C also make use of the unsafe types uintptr and unsafe.Pointer.

Are their pointers compatible ? Go runs on a native Vm, so I guessed there might be an abstraction layer over the memory that invalidates C/C++ pointers

Pointers are compatible.

Answer 2

It is possible, indeed. There are some bindings already done (wxWidgets, FLTK and GTK).

Please note that to link code with the original compiler, it must use the same format and calling conventions, so it's quite useless.

Gccgo on the other hand is standard and can interact in any desired way (but requires some care). It can also create shared libraries.

Take a look at the documentation.

Answer 3

Not directly, You will have to port (read as rewrite) your C or C++ code because Go is not source-level compatible with C. If you want a modern language which is source-level compatible with C (well, almost), try the D programming language. Both Go and D are not source-level compatible with C++. I do not know about Go, but D has a limited "understanding" of C++ through the extern(C++).

Answer 4

No I don't believe so. In particular, C/C++ compatibility is hampered by:

• Lack of a mature frontend to a well supported mainstream compiler such as GCC or LLVM.
• Impedance mismatch between threads and goroutines. More specifically, foreign threads cannot call into the Go machinery and vice versa. Many C/C++ libraries make use of threads and callbacks in their interfaces.
• Inability to call functions that block on I/O or system resources. This limits what libraries and functions you can call from goroutines without endangering the Go scheduler.