consider using __cpp_exceptions and/or __EXCEPTIONS to disable/enable exception support

[user1095108]

It is much more user-friendly if exception support is automatically detected.

resources:
https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_exceptions.html
http://en.cppreference.com/w/cpp/experimental/feature_test

[nlohmann]

Thanks, I did not find these macros. Do you know which compilers are covered with them?

[user1095108]

gcc and clang definitely, others I don't know. You can test for a specific compiler than go on from there. But it is a proposed standard extension too.

[user1095108]

I guess you could also do #if defined(__cpp_exceptions) && (1 == __cpp_exceptions)

No need to a specific compiler test then.

[nlohmann]

I'm checking for __EXCEPTIONS right now. No idea where I got this from...

[user1095108]

If you do it doesn't work too well :) I tried to compile without exception support and it didn't work, I checked and saw I'd have to define some macro manually to get your library to compile.

[nlohmann]

@user1095108 I added a fix (see 65dfc97). Does this work for you?

[nlohmann]

Sigh... MSVC seems not to use __cpp_exceptions (Appveyor fails: https://ci.appveyor.com/project/nlohmann/json/build/1770). I read about _HAS_EXCEPTIONS so far, but did not find a reliable source for that.

[user1095108]

I'd still check if __cpp_exceptions is defined. The macro is not part of c++98, just the exceptions themselves. Otherwise, great.

[nlohmann]

I'd still check if __cpp_exceptions is defined.

What do you mean?

[nlohmann]

From https://msdn.microsoft.com/en-us/library/b0084kay.aspx:

_CPPUNWIND Defined as 1 if one or more of the /GX (Enable Exception Handling), /clr (Common Language Runtime Compilation), or /EH (Exception Handling Model) compiler options are set. Otherwise, undefined.

[user1095108]

It is a proposed extension of c++, gcc and clang already implement it, but MSVC has its own thing as you noticed.

[nlohmann]

I see. If the fix works for you, I can close the ticket.

[user1095108]

sure, but you won't put this into the main branch? I think you want a generic solution. 2017-03-11 18:21 GMT+01:00 Niels Lohmann <notifications@github.com>:

…

I see. If the fix works for you, I can close the ticket. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#498 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AH6jVGjolDowt0m-MvgkoO2kWEv2h4ITks5rktgUgaJpZM4MaOyK> .

[nlohmann]

I will, but first I wanted your OK, and I want to wait for Travis to finish.

[user1095108]

ok, as I wrote earlier, I'd check #if defined(__cpp_exceptions) && (1 == __cpp_exceptions) ... You may have your preferences though, maybe an existent macro definition could override everything. 2017-03-11 18:36 GMT+01:00 Niels Lohmann <notifications@github.com>:

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I will, but first I wanted your OK, and I want to wait for Travis to finish. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#498 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AH6jVOPlw9gr1YvjtAsyXfYDM-SQ-xynks5rktuQgaJpZM4MaOyK> .

[nlohmann]

You're right, it is better to used defined(). But I would not care about the value of the macro - if someone defines it, it better has the standard semantics.

[user1095108]

I'm ok with this. g++ -x c++ -dM -E - < /dev/null | grep _cpp_exceptions 2017-03-11 18:44 GMT+01:00 Niels Lohmann <notifications@github.com>:

…

You're right, it is better to used defined(). But I would not care about the value of the macro - if someone defines it, it better has the standard semantics. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#498 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AH6jVExKCs_UCxw8ct0NT0k7BLxVQptfks5rkt2SgaJpZM4MaOyK> .

[nlohmann]

$ g++ -x c++ -dM -E - < /dev/null | grep _cpp_exceptions

#define __cpp_exceptions 199711

[user1095108]

Yes, you might want to use that or just check if it is defined :) 2017-03-11 18:53 GMT+01:00 Niels Lohmann <notifications@github.com>:

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$ g++ -x c++ -dM -E - < /dev/null | grep _cpp_exceptions #define __cpp_exceptions 199711 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#498 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AH6jVF8yJZ-EN3yL0VIot22yO8x-IsXpks5rkt-agaJpZM4MaOyK> .

[nlohmann]

GCC 4.9 does not define __cpp_exceptions. I might need __EXCEPTIONS there.

[user1095108]

It's your library, I personally don't care about 4.9 anymore. 2017-03-11 20:09 GMT+01:00 Niels Lohmann <notifications@github.com>:

…

GCC 4.9 does not define __cpp_exceptions. I might need __EXCEPTIONS there. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#498 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AH6jVGHAETwHtKvUrOvksE6PsHh0fk6aks5rkvFpgaJpZM4MaOyK> .