Please can you add extern "C" as appropriate to your header files?

RE: Please can you add extern "C" as appropriate to your header files?

Peter Kenyon — Sat, 19 May 2018 05:01:16 GMT

I am using SDK 15 and I noticed that nrf_pwr_mgmt.h is missing the C++ guards, so an easy fix for the next release.

Also I had an issue with.. lines 205 in app_util.h

#ifdef __GNUC__
#define STATIC_ASSERT_SIMPLE(EXPR)      //_Static_assert(EXPR, "unspecified message")
#define STATIC_ASSERT_MSG(EXPR, MSG)    //_Static_assert(EXPR, MSG)
#endif

The approach I have adopted is to define the state of the app using a set of vtables (classes) so C++ is essential.

I am using the excellent SES and C++ 11

RE: Please can you add extern "C" as appropriate to your header files?

Christopher — Mon, 21 Mar 2016 18:34:18 GMT

From SDK11, the header files of SoftDevices s130 and s130 now include the #ifdef __cplusplus wrapper. Unfortunately, the header files of the SDK (hal, drivers, libraries) have not been updated yet.

RE: Please can you add extern "C" as appropriate to your header files?

Andrew Kohlsmith — Wed, 18 Jun 2014 15:50:29 GMT

I think including the guards is a great idea but I admit I did laugh out loud at the claim of total superiority. :-)

RE: Please can you add extern "C" as appropriate to your header files?

Eirik Midttun — Fri, 06 Jun 2014 17:41:47 GMT

If you ask me it is matter of habit; looks strange if you are not used to it. Andrew has a fair point that the mbed platform is supported. That does make a case for including the C++ include guards as suggested.

RE: Please can you add extern "C" as appropriate to your header files?

Tim — Fri, 06 Jun 2014 13:12:15 GMT

That does work, it's just inconvenient and error-prone (sometimes you forget). It's like if you had to do all your own #include guards.

RE: Please can you add extern "C" as appropriate to your header files?

Andrew Fernandes — Wed, 28 May 2014 11:44:22 GMT

I would vote for the C++ include guards, too!

This is standard style if a C interface supports C++, even if "support" means "is not painful to use". Cognitive style is very important in C, so using "standard" idioms, such as __cplusplus guards, really helps take the cognitive load off of a developer.

Also, the mbed platform is C++ only, and I know that Nordic is supporting that, so I would assume that C++ is actually, to some extent, already supported by Nordic using a mbed branch of the SDK!

RE: Please can you add extern "C" as appropriate to your header files?

Joe Merten — Wed, 28 May 2014 08:47:00 GMT

As I'm also using C++ (gcc-arm) with Nordic Sdk, I'm with you. Using extern "C" { #include "sdklib.h" } in every of my C++ sources works, but appears a bit ugly.

RE: Please can you add extern "C" as appropriate to your header files?

Eirik Midttun — Tue, 27 May 2014 19:55:12 GMT

The header files don't have the extern "C" wrapping because the SDK isn't designed with C++ in mind. As long as that is the decision I don't think the header files should include C++ directives for mere convenience.

I'm a bit unsure how you actually wrap from the question, but I see nothing wrong with something like this in a .cpp file:

extern "C" {
#include "sdklib.h"
}

Is that so difficult? I would prefer it like this this; it is a nice reminder that sdklib is in pure C, not C++ as the rest of the code.

RE: Please can you add extern "C" as appropriate to your header files?

Nguyen Hoan Hoang — Wed, 21 May 2014 12:52:26 GMT

I second you on this. It MUST always be there for all exposed C function.

RE: Please can you add extern "C" as appropriate to your header files?

Tim — Wed, 21 May 2014 12:23:18 GMT

Actually the "impossible constraint in asm" issue was something else, but the point still stands.