Open Radar

 
Summary:
The CFType functions declared in Core Foundation are exported to the global namespace and can cause a name collision with an unfortunately same-named C++ namespace.

For example, the following code fails to compile, resulting with an error of "redefinition of 'CFHash' as different kind of symbol":

//--- begin code snippet ---
#import <CoreFoundation/CoreFoundation.h>
namespace CFHash {
	class SHA512 {
	};
}
//--- end code snippet ---

Given that renaming the CFType functions would be impossible without API breakage, is there a possibility to add a #define to control renaming of these function calls to a less common name, or even completely skipping their declarations?

Perhaps something similar to the __ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORES found in AssertMacros.h would be helpful.

Steps to Reproduce:


Expected Results:
The above code snippet compiles without a compile error.

Actual Results:
clang errors with:

/Users/falken/src/ColdFusion/tests/main.cpp:2:11: error: redefinition of 'CFHash' as different kind of symbol
namespace CFHash {
          ^
In file included from /Users/falken/src/ColdFusion/tests/main.cpp:1:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:38:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CFBase.h:630:12: note: previous definition is here
CFHashCode CFHash(CFTypeRef cf);
           ^
1 error generated.


Version:
Xcode 7.3.1 (7D1014), OS X 10.11 SDK, OS X 10.11.4

Notes:
Since the CFHash() function does not conflict with a C++ namespace at link time, one workaround is to use a preprocessor #define to rename the CFHash() function to something else, then include the header.

For example, the following code compiles without issue:

#define CFHash __Apple_CFHash
#import <CoreFoundation/CoreFoundation.h>
#undef CFHash
namespace CFHash {
	class Test {
	};
}


Configuration:


Attachments: