/.../QrCode.cpp:400: error: 'INT32_MAX' was not declared in this scope int32_t minPenalty = INT32_MAX; ^ about qr-code-generator

[nayuki]

(Related to http://stackoverflow.com/a/39951669/839689 and https://github.com/mrdeveloperdude/OctoMY/blob/master/libs/libqr/QrCode.cpp )

Hello Lennart! A couple of things going on here:

• INT32_MAX is defined in stdint.h (a.k.a. cstdint). QrCode.cpp doesn't #include the header file, but it includes QrCode.hpp which does #include <cstdint>.
• You may replace all int32_t with qint32, et cetera. My hunch is that this is just extra work without any benefit, because if I understand correctly, stdint.h should be supported pervasively by now.

[mrdeveloperdude]

Yes. Im å purist. Bug is that INT32_MAX is not defined in android ndk toolchain even when <cstdint> is include. So much for pervasively supporter :p On Dec 16, 2016 11:44 PM, "Nayuki" <[email protected]> wrote: (Related to http://stackoverflow.com/a/39951669/839689 ) Hello Lennart! A couple of things going on here: - INT32_MAX is defined in stdint.h (a.k.a. cstdint). QrCode.cpp doesn't #include the header file, but it includes QrCode.hpp which does #include <cstdint>. - You may replace all int32_t with qint32, et cetera. My hunch is that this is just extra work without any benefit, because if I understand correctly, stdint.h should be supported pervasively by now. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AD6XTPFuqkmKGM8rPO5ma2dDdrL2dTZ_ks5rIxQ8gaJpZM4LOyLT> .

[nayuki]

That's a troubling discovery. If I understand correctly, stdint.h must be fully supported if the compiler supports C++11. I suggest some options for you:

• Try writing std::INT32_MAX just in case that symbol is in the std namespace and not in the global namespace.
• Try changing the include of cstdint to stdint.h (related to namespace conventions).
• Simply write out the constant 2147483647, because INT32_MAX must have the same value on every platform (unlike INT_MAX).

[mrdeveloperdude]

Thanks for suggestions! I already put the constant in, that of course works great :) I will also try std:: namespace, I did not even think of it. It could indeed be a problem in my code. I prefer not to use the "using" keyword. Also recommended is to use <cstdint> in C++ instead of <stdint.h>, usually the first will include the other (I checked, wrapped in a serious amount of macro trickery there actually is such an inclusion in Android NDK so that was kind of puzzling to me. ) Again thanks.

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On Sat, Dec 17, 2016 at 6:05 PM, Nayuki ***@***.***> wrote: That's a troubling discovery. If I understand correctly, INT32_MAX is guaranteed to be in stdint.h, which must be supported if the compiler supports C++11. I suggest two options for you: - Try writing std::INT32_MAX just in case that symbol is in the std namespace and not in the global namespace. - Try including stdint.h instead of cstdint. - Simply write out the constant 2147483647 <(214)%20748-3647>, because INT32_MAX must have the same value on every platform (unlike INT_MAX). — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AD6XTPcLUHhrun6GklgwAIZPxxXuHB-4ks5rJBZygaJpZM4LOyLT> .

[nayuki]

It's okay to avoid using the using keyword. For one usage, it's probably better to write out the fully qualified name like std::INT32_MAX.

I think you're right that it is recommended to use <cstdint> instead of <stdint.h>. It agrees better with C++ conventions.

There is a general confusion about whether items that were defined globally in C are present globally in C++ or must be accessed through namespace std. See discussions like this for example: http://stackoverflow.com/questions/32606023/when-using-c-headers-in-c-should-we-use-functions-from-std-or-the-global-na