{"id":61,"date":"2012-02-15T16:56:00","date_gmt":"2012-02-15T16:56:00","guid":{"rendered":"https:\/\/www.root42.de\/blog\/?p=61"},"modified":"2012-02-15T16:56:00","modified_gmt":"2012-02-15T16:56:00","slug":"what-about-c11-in-xcode","status":"publish","type":"post","link":"https:\/\/www.root42.de\/blog\/?p=61","title":{"rendered":"What about C++11 in Xcode?"},"content":{"rendered":"

This started out as a very small problem: I am using C++, Objective C++ and Objective C mixed in one project. This usually works pretty well. However, when including MapKit, the compiler choked on an Objective C++ file. It seems the MapKit.h header wants to use isinf(). This function has been introduced with ISO C 99, but it it is not included in ISO C++ 98. Hence the failure of Xcode’s gcc and clang compilers.<\/p>\n

To work around this problem I was thinking of trying to set the project settings to use ISO C++ 11, or C++ 0x, since Xcode’s compilers are not that<\/i> up to date. This is pretty easy:<\/p>\n

<\/a><\/div>\n

And I guess this would work for most people. However, I am also using boost in this project. And I guess it is rather up to date, concerning the new language specification. However this also means that there is a problem with clang’s support of the language. I get a ton of errors in boost when switching to C++ 0x in clang:<\/p>\n

<\/a><\/div>\n

In short, I think the C++ 11 support is not quite there yet with Xcode 4.2 and clang 3.0. I will try to post updates when future Xcode releases are coming out. If, alternatively, someone has hints on how to compile boost with clang 3.0, I am also glad to try that out.<\/p>\n

Update:<\/b> There is a fork on gitorious<\/a> of the boost on iPhone build script, which already uses the clang compiler. I hacked the script even more to use –std=c++0x<\/span> as a flag and it builds fine. Now I will try to link this new framework to an iOS project compiled with clang using C++ 0x.<\/p>\n

Update 2:<\/b> I found the root of the problem. The fantastic people over at #boost <\/span>on freenode<\/a> helped me figuring it out. In short: boost::fusion<\/a> defines nil<\/span>, which is an Objective C keyword. Thus we get lots of problems. Objective C defines nil<\/span> and Nil<\/span> in objc\/objc.h<\/span>. A minimal program that compiles successfully:<\/p>\n

#include <boost\/phoenix\/core\/reference.hpp>
#import <CoreFoundation\/CoreFoundation.h>

int main()
{
    return 1;
}
<\/pre>\n
Using this command line: <\/p>\n
\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/usr\/bin\/clang++ 
-isysroot \/Developer\/Platforms\/iPhoneOS.platform\/Developer\/SDKs\/iPhoneOS5.0.sdk 
-framework Foundation -Fpath\/to\/boost\/framework --std=c++0x -arch armv7 
-stdlib=libc++ -mthumb -miphoneos-version-min=5.0 foo.mm -o foo 
<\/pre>\n
If you swap the to include \/ import statements, the program will not compile, since now the ObjC nil makes boost break. There is a boost ticket<\/a> tracking this issue, with a proposed patch attached, which renames the boost nil<\/span> to nil_<\/span>.<\/p>\n
Update 3:<\/b> The patch works fine, but now I get internal compiler errors from clang. The compile triggers a segmentation violation at some point during the compilation of my project. I guess clang 3.0 is still a bit experimental. I submitted a bug report and will revert to using the default settings of Xcode for the time being.<\/p>\n","protected":false},"excerpt":{"rendered":"
This started out as a very small problem: I am using C++, Objective C++ and Objective C mixed in one project. This usually works pretty well. However, when including MapKit, the compiler choked on an Objective C++ file. It seems the MapKit.h header wants to use isinf(). This function has been introduced with ISO C … Continue reading “What about C++11 in Xcode?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[38,7,45,24],"tags":[],"_links":{"self":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts\/61"}],"collection":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=61"}],"version-history":[{"count":0,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=\/wp\/v2\/posts\/61\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=61"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=61"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.root42.de\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=61"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}