Xcode 由于 libkern.h 中的语义问题，构建失败

Question

我正在尝试从 Xcode 中的 GitHub (https://github.com/i3roly/CMI8788) 编译声卡驱动程序，但我遇到了两个我根本不理解的语义问题。我真的很困惑，因为问题不在代码本身，而在 macOS 框架中。这是关于文件 libkern.h

我尝试在 Xcode 9 上编译它，因为我认为这可能是 Xcode 10 的问题。同样的结果。

关于libkern.h的那部分：

extern int  ffs(int);
extern int  ffsll(unsigned long long);
extern int  fls(int);
extern int  flsll(unsigned long long);
extern u_int32_t    random(void);
extern int  scanc(u_int, u_char *, const u_char *, int);
extern int  skpc(int, int, char *);
extern long strtol(const char*, char **, int);
extern u_long   strtoul(const char *, char **, int);
extern quad_t   strtoq(const char *, char **, int);
extern u_quad_t strtouq(const char *, char **, int);
extern char *strsep(char **, const char *);
extern void *memchr(const void *, int, size_t);
extern void url_decode(char *str);

这是日志文件中的结果：

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/IOKit/IOLib.h:44:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/IOKit/system.h:57:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/libkern/libkern.h:145:12: error: conflicting types for 'ffsll'
extern int      ffsll(unsigned long long);
                ^
In file included from /Users/jakob/Documents/CMI8788/CMI8788/XonarHDAVAudioEngine.cpp:47:
In file included from /usr/include/string.h:180:
/usr/include/strings.h:86:6: note: previous declaration is here
int      ffsll(long long) __OSX_AVAILABLE_STARTING(__MAC_10_9, __IPHONE_7_0);
         ^
In file included from /Users/jakob/Documents/CMI8788/CMI8788/XonarHDAVAudioEngine.cpp:49:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/IOKit/IOLib.h:44:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/IOKit/system.h:57:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks/Kernel.framework/Headers/libkern/libkern.h:147:12: error: conflicting types for 'flsll'
extern int      flsll(unsigned long long);

我希望有人能告诉我这是怎么回事。谢谢！

Answer 1

问题出在the following line:

#import </usr/include/string.h>

不要包含具有绝对路径的文件。 Kernel.framework 有自己的 string.h 版本，您可以通过 #include <string.h> 包含它。 User-space 头文件可能会在构建 kext 时导致构建错误或更微妙的问题。不要使用它们。

上面那条线，

#import </usr/include/libkern/OSAtomic.h>

也应该使用相对路径：<libkern/OSAtomic.h>

旁注：

使用 #import (Objective-C) 可能对 C 和 C++ 头文件有效，也可能无效；有时它们在后续 #include 指令中的行为会有所不同，因此如果您有任何其他问题，请切换到 #include.

Xcode 由于 libkern.h 中的语义问题，构建失败

Xcode Build failed because of Semantic Issues in libkern.h

c++

xcode

macos

iokit

kernel-extension