Question

我正在使用跨平台的C ++库。虽然该库试图不可知，但它确实与Cocoa / CocoaTouch安全框架等框架集成。

在现代Darwin系统上，如OS X 107,10.8和10.9（以及iOS等价物），以下工作正常。现代系统使用Xcode 4.3及以上版本。

$ make
...
/opt/local/bin/clang++-mp-3.4  -m64 -pthread -stdlib=libc++ -fPIC -fvisibility=hidden
-std=c++11 -D_REENTRANT -fstack-protector -O3 -Wall -Wextra -Ibuild/include
-c ./src/lib/entropy/darwin_secrandom/darwin_secrandom.cpp -o build/obj/lib/entropy_darwin_secrandom.o

./src/lib/entropy/darwin_secrandom/darwin_secrandom.cpp:10:10: fatal error: 
      'Security/SecRandom.h' file not found
#include <Security/SecRandom.h>
         ^
1 error generated.
make: *** [build/obj/lib/entropy_darwin_secrandom.o] Error 1

在使用Xcode 3.1运行OS X 10.5的旧版PowerMac上，include会导致compile error。较旧的PowerMac仍在测试中，因为它是一个大端的PowerPC cpu。

<Security/SecRandom.h>

我的问题是，我们如何判断TargetConditionals.h何时可用？它与Xcode 4及以上版本有关吗？或者它与其他东西联系在一起？如果是这样，我们使用什么预处理器宏来检测可用性？

当我查看预处理器宏时，我看不到用于向用户发送信号的内容。显然，MacPorts编译器正在集成（或意识到）Cocoa和CocoaTouch等框架，因为我们可以包含像$ /opt/local/bin/clang++-mp-3.4 -m64 -pthread -stdlib=libc++ -fPIC -include TargetConditionals.h -x c++ -dM -E - < /dev/null | sort #define OBJC_NEW_PROPERTIES 1 #define TARGET_CPU_68K 0 #define TARGET_CPU_ALPHA 0 #define TARGET_CPU_MIPS 0 #define TARGET_CPU_PPC 1 #define TARGET_CPU_PPC64 0 #define TARGET_CPU_SPARC 0 #define TARGET_CPU_X86 0 #define TARGET_CPU_X86_64 0 #define TARGET_OS_EMBEDDED 0 #define TARGET_OS_MAC 1 #define TARGET_OS_UNIX 0 #define TARGET_OS_WIN32 0 #define TARGET_RT_64_BIT 0 #define TARGET_RT_BIG_ENDIAN 1 #define TARGET_RT_LITTLE_ENDIAN 0 #define TARGET_RT_MAC_CFM 0 #define TARGET_RT_MAC_MACHO 1 #define _ARCH_PPC 1 #define _ARCH_PPC64 1 #define _BIG_ENDIAN 1 #define _LP64 1 #define _REENTRANT 1 #define __APPLE_CC__ 6000 #define __APPLE__ 1 #define __ATOMIC_ACQUIRE 2 #define __ATOMIC_ACQ_REL 4 #define __ATOMIC_CONSUME 1 #define __ATOMIC_RELAXED 0 #define __ATOMIC_RELEASE 3 #define __ATOMIC_SEQ_CST 5 #define __BIG_ENDIAN__ 1 #define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ #define __CHAR16_TYPE__ unsigned short #define __CHAR32_TYPE__ unsigned int #define __CHAR_BIT__ 8 #define __CONSTANT_CFSTRINGS__ 1 #define __DBL_DENORM_MIN__ 4.9406564584124654e-324 #define __DBL_DIG__ 15 #define __DBL_EPSILON__ 2.2204460492503131e-16 #define __DBL_HAS_DENORM__ 1 #define __DBL_HAS_INFINITY__ 1 #define __DBL_HAS_QUIET_NAN__ 1 #define __DBL_MANT_DIG__ 53 #define __DBL_MAX_10_EXP__ 308 #define __DBL_MAX_EXP__ 1024 #define __DBL_MAX__ 1.7976931348623157e+308 #define __DBL_MIN_10_EXP__ (-307) #define __DBL_MIN_EXP__ (-1021) #define __DBL_MIN__ 2.2250738585072014e-308 #define __DECIMAL_DIG__ 33 #define __DEPRECATED 1 #define __DYNAMIC__ 1 #define __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ 1050 #define __EXCEPTIONS 1 #define __FINITE_MATH_ONLY__ 0 #define __FLT_DENORM_MIN__ 1.40129846e-45F #define __FLT_DIG__ 6 #define __FLT_EPSILON__ 1.19209290e-7F #define __FLT_EVAL_METHOD__ 0 #define __FLT_HAS_DENORM__ 1 #define __FLT_HAS_INFINITY__ 1 #define __FLT_HAS_QUIET_NAN__ 1 #define __FLT_MANT_DIG__ 24 #define __FLT_MAX_10_EXP__ 38 #define __FLT_MAX_EXP__ 128 #define __FLT_MAX__ 3.40282347e+38F #define __FLT_MIN_10_EXP__ (-37) #define __FLT_MIN_EXP__ (-125) #define __FLT_MIN__ 1.17549435e-38F #define __FLT_RADIX__ 2 #define __GCC_ATOMIC_BOOL_LOCK_FREE 2 #define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2 #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2 #define __GCC_ATOMIC_CHAR_LOCK_FREE 2 #define __GCC_ATOMIC_INT_LOCK_FREE 2 #define __GCC_ATOMIC_LLONG_LOCK_FREE 2 #define __GCC_ATOMIC_LONG_LOCK_FREE 2 #define __GCC_ATOMIC_POINTER_LOCK_FREE 2 #define __GCC_ATOMIC_SHORT_LOCK_FREE 2 #define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1 #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2 #define __GNUC_GNU_INLINE__ 1 #define __GNUC_MINOR__ 2 #define __GNUC_PATCHLEVEL__ 1 #define __GNUC__ 4 #define __GNUG__ 4 #define __GXX_ABI_VERSION 1002 #define __GXX_RTTI 1 #define __GXX_WEAK__ 1 #define __INT16_TYPE__ short #define __INT32_TYPE__ int #define __INT64_C_SUFFIX__ L #define __INT64_TYPE__ long int #define __INT8_TYPE__ char #define __INTMAX_MAX__ 9223372036854775807L #define __INTMAX_TYPE__ long int #define __INTMAX_WIDTH__ 64 #define __INTPTR_TYPE__ long int #define __INTPTR_WIDTH__ 64 #define __INT_MAX__ 2147483647 #define __LDBL_DENORM_MIN__ 4.94065645841246544176568792868221e-324L #define __LDBL_DIG__ 31 #define __LDBL_EPSILON__ 4.94065645841246544176568792868221e-324L #define __LDBL_HAS_DENORM__ 1 #define __LDBL_HAS_INFINITY__ 1 #define __LDBL_HAS_QUIET_NAN__ 1 #define __LDBL_MANT_DIG__ 106 #define __LDBL_MAX_10_EXP__ 308 #define __LDBL_MAX_EXP__ 1024 #define __LDBL_MAX__ 1.79769313486231580793728971405301e+308L #define __LDBL_MIN_10_EXP__ (-291) #define __LDBL_MIN_EXP__ (-968) #define __LDBL_MIN__ 2.00416836000897277799610805135016e-292L #define __LONG_DOUBLE_128__ 1 #define __LONG_LONG_MAX__ 9223372036854775807LL #define __LONG_MAX__ 9223372036854775807L #define __LP64__ 1 #define __MACH__ 1 #define __NATURAL_ALIGNMENT__ 1 #define __NO_INLINE__ 1 #define __ORDER_BIG_ENDIAN__ 4321 #define __ORDER_LITTLE_ENDIAN__ 1234 #define __ORDER_PDP_ENDIAN__ 3412 #define __PIC__ 2 #define __POINTER_WIDTH__ 64 #define __POWERPC__ 1 #define __PPC64__ 1 #define __PPC__ 1 #define __PRAGMA_REDEFINE_EXTNAME 1 #define __PTRDIFF_TYPE__ long int #define __PTRDIFF_WIDTH__ 64 #define __REGISTER_PREFIX__ #define __SCHAR_MAX__ 127 #define __SHRT_MAX__ 32767 #define __SIG_ATOMIC_WIDTH__ 32 #define __SIZEOF_DOUBLE__ 8 #define __SIZEOF_FLOAT__ 4 #define __SIZEOF_INT128__ 16 #define __SIZEOF_INT__ 4 #define __SIZEOF_LONG_DOUBLE__ 16 #define __SIZEOF_LONG_LONG__ 8 #define __SIZEOF_LONG__ 8 #define __SIZEOF_POINTER__ 8 #define __SIZEOF_PTRDIFF_T__ 8 #define __SIZEOF_SHORT__ 2 #define __SIZEOF_SIZE_T__ 8 #define __SIZEOF_WCHAR_T__ 4 #define __SIZEOF_WINT_T__ 4 #define __SIZE_MAX__ 18446744073709551615UL #define __SIZE_TYPE__ long unsigned int #define __SIZE_WIDTH__ 64 #define __STDC_HOSTED__ 1 #define __STDC_UTF_16__ 1 #define __STDC_UTF_32__ 1 #define __STDC__ 1 #define __TARGETCONDITIONALS__ #define __UINTMAX_TYPE__ long unsigned int #define __USER_LABEL_PREFIX__ _ #define __VERSION__ "4.2.1 Compatible Clang 3.4.2 (tags/RELEASE_34/dot2-final)" #define __WCHAR_MAX__ 2147483647 #define __WCHAR_TYPE__ int #define __WCHAR_WIDTH__ 32 #define __WINT_TYPE__ int #define __WINT_WIDTH__ 32 #define __clang__ 1 #define __clang_major__ 3 #define __clang_minor__ 4 #define __clang_patchlevel__ 2 #define __clang_version__ "3.4.2 (tags/RELEASE_34/dot2-final)" #define __cplusplus 199711L #define __llvm__ 1 #define __pic__ 2 #define __powerpc64__ 1 #define __powerpc__ 1 #define __ppc64__ 1 #define __ppc__ 1 #define __private_extern__ extern #define __strong #define __unsafe_unretained #define __weak __attribute__((objc_gc(weak)))这样的标题：

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Answer 1

如果查看标题，您会看到函数已注释__OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_2_0)。

这意味着它们自OS_X 10.7和iOS 2.0起可用。

您可以在编译期间检查特定的宏。

检测<secure secrandom.h =“”>的可用性？

1 个答案: