Objective-C++ compilation errors due to Xcode not respecting file type -

i'm following tutorial in book (iphone 3d programming), uses:

• objective-c header , source files (file extensions .h, .m - respectively),
• objective-c++ header , source files (file extensions .h, .mm - respectively)
• c++ header , source files (file extensions .hpp, .mpp - respectively)

a sample xcode project included compiles successfully.

before found sample project, had manually typed out code book getting following compilation errors files detailed below:

1. unknown type name 'virtual'
2. expected member name or ';' after declaration specifiers

irenderingengine.hpp (xcode file inspector - file type = "default - c++ header")

... struct irenderingengine {     virtual void initialize(int width, int height) = 0; //2 errors marked above     virtual void render() const = 0; //2 errors marked above     virtual void updateanimation(float timestep) = 0; //2 errors marked above     virtual void onrotate(deviceorientation neworientation) = 0; //2 errors marked above     virtual ~irenderingengine() {} //2 errors marked above }; ... 

1. must use 'struct' tag refer type 'irenderingengine'

glview.h (xcode file inspector - file type = "default - c header")

#import "irenderingengine.hpp" #import <quartzcore/quartzcore.h>  @interface glview : uiview { @private     eaglcontext* m_context;     irenderingengine* m_renderingengine; //1 error marked above     float m_timestamp; }  - (void) drawview:(cadisplaylink*)displaylink; - (void) didrotate:(nsnotification*)notification;  @end 

the file types other files defaulted expected file types in xcode file inspector , such should have worked correctly build setting - apple llvm compiler 4.2 - language - "compile sources = according file type" - identical build setting in sample project compiles successfully.

for odd reason changing build setting "compile sources = objective-c++" in manually created project removed compilation errors , application ran expected.

can offer reason why setting not consistent between seemingly identical (source-code-wise) projects?

header files not compiled. header files used preprocessor — anywhere have #include or #import actual text of original treated though you'd copied , pasted original.

hence doesn't matter if file called .hpp, .h or else. if .m file imports .h file includes .hpp file .hpp code compiled part of .m file, i.e. objective-c.

i therefore going guess you've got glview.m. if that's going import .hpp file, whether directly or indirectly, needs compiled objective-c++. 1 way rename .mm, other tell project not try guess language types file extension.