Added a c based re-entrant critical section API

[adbridge]

@bogdanm @bremoran

[0xc0170]

• Update the license to use latest one (with SPDX)
• Do the same as the closing one, don't align them.

#ifdef __cplusplus
namespace mbed {
namespace util {
extern "C" {
#endif

• Use doxygen for API documentation

• include is in the header file ?

[bogdanm]

LGTM, but we also need to make the C++ implementation use the C implementation. Otherwise we'll end up with two parallel locking mechanisms, each with its own logic. This might seems out of scope for the original "create a C locking mechanism", but for the sake of consistency I believe we also need to modify the C++ implementation as part of this PR.

[adbridge]

@bogdanm Do we want to do that for the release? Bearing in mind that the c-based solution was added primarily to fix the https://github.com/ARMmbed/sal-driver-lwip-k64f-eth/issues/3 Although that actual fix should be very quick now we have an implementation.

[bogdanm]

Yes, that's what I was thinking too: it should be quite easy to re-write the C++ solution in terms of the C solution.

[adbridge]

@0xc0170 @bogdanm @bremoran review comments done

[bogdanm]

Why did you put critical.h under mbed-util instead of the existing core-util ?

[adbridge]

@bogdanm As that is where Brendan put it in his original proposal

[bogdanm]

Ah OK, that might've been before we renamed the repos. Please move it to core-util.

[bremoran]

Will this critical section work on NRF51? What about POSIX?

[bremoran]

Notwithstanding my previous comment, can we merge this first, then add support for POSIX and NRF51?

[adbridge]

@bogdanm @bremoran @0xc0170 additional comments done and re-tested, can we do a quick check and then merge.

[rgrover]

can you please add JIRA tickets for @pan- and I to complete testing against NRF51 and POSIX?

[bremoran]

LGTM

[bogdanm]

+1

[bogdanm]

Published new version 1.5.0