Fix 'recv' function 'flags_' argument default value

[xiphon]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 246

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.3%) to 85.62%

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Files with Coverage Reduction	New Missed Lines	%
zmq.hpp	4	83.14%

Totals
Change from base Build 243:	-0.3%
Covered Lines:	649
Relevant Lines:	758

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💛 - Coveralls

[sigiesec]

Thanks for the PR!

It's not completely clear to me what problem this fixes. Could you add a test case that is fixed by your change?

[xiphon]

flags_ argument was defaulted to 0 previously (v4.3.0), i.e. bool recv(message_t *msg_, int flags_ = 0); https://github.com/zeromq/cppzmq/blob/v4.3.0/zmq.hpp#L722

That was obviously accidentally changed in 3d4be81 resulting in non-optional flags_ breaking backward compatibility for client code invoking bool result = recv(&msg); call.

Let me know if you have any further questions.

[xiphon]

Updated. Added a test case.

[gummif]

You are correct that this is a bug, and I think the fix is simply removing the #ifdef completely, that is int flags_ = 0 as it was before.

[xiphon]

Updated