如何通过android ndk在C/C++文件中检测编译？

Question

是否有一个预处理宏，让我知道ndk正在编译我的代码？我可以手动定义我自己的，但我宁愿不可能。

Answer 1

它是#ifdef __ANDROID__通过运行预处理器看出：

~$ /usr/local/android-ndk-r6/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc -E -dM - < /dev/null | grep -i android 

输出是：

#define __ANDROID__ 1 

不需要依赖于定义的东西在你的项目特别是如果你跳过NDK构建系统。

Answer 2

简短回答：#ifdef ANDROID。

的ANDROID宏您在build-module.mk定义（标准构建系统的一部分）：

# always define ANDROID when building binaries 
# 
LOCAL_CFLAGS := -DANDROID $(LOCAL_CFLAGS) 

Answer 3

这是一个迟到的答案，但为了完整起见，这里是包含任何头文件之前的android-eabi的预处理器定义。一个C++头文件将带来一大堆额外的头文件。

以下输出来自Android NDK邮件列表上的Detecting Android in C/C++ Source Files (Preprocessor Macros)（大约2013年）。通知__ANDROID__被定义，但不是__android__或ANDROID。

$ arm-linux-androideabi-cpp -dM < /dev/null | sort 
#define __ANDROID__ 1 
#define __APCS_32__ 1 
#define __ARMEL__ 1 
#define __ARM_ARCH_5TE__ 1 
#define __ARM_EABI__ 1 
#define __ARM_FEATURE_DSP 1 
#define __ARM_PCS 1 
#define __BIGGEST_ALIGNMENT__ 8 
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ 
#define __CHAR16_TYPE__ short unsigned int 
#define __CHAR32_TYPE__ unsigned int 
#define __CHAR_BIT__ 8 
#define __CHAR_UNSIGNED__ 1 
#define __DBL_DECIMAL_DIG__ 17 
#define __DBL_DENORM_MIN__ ((double)4.9406564584124654e-324L) 
#define __DBL_DIG__ 15 
#define __DBL_EPSILON__ ((double)2.2204460492503131e-16L) 
#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__ ((double)1.7976931348623157e+308L) 
#define __DBL_MIN_10_EXP__ (-307) 
#define __DBL_MIN_EXP__ (-1021) 
#define __DBL_MIN__ ((double)2.2250738585072014e-308L) 
#define __DEC128_EPSILON__ 1E-33DL 
#define __DEC128_MANT_DIG__ 34 
#define __DEC128_MAX_EXP__ 6145 
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL 
#define __DEC128_MIN_EXP__ (-6142) 
#define __DEC128_MIN__ 1E-6143DL 
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL 
#define __DEC32_EPSILON__ 1E-6DF 
#define __DEC32_MANT_DIG__ 7 
#define __DEC32_MAX_EXP__ 97 
#define __DEC32_MAX__ 9.999999E96DF 
#define __DEC32_MIN_EXP__ (-94) 
#define __DEC32_MIN__ 1E-95DF 
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF 
#define __DEC64_EPSILON__ 1E-15DD 
#define __DEC64_MANT_DIG__ 16 
#define __DEC64_MAX_EXP__ 385 
#define __DEC64_MAX__ 9.999999999999999E384DD 
#define __DEC64_MIN_EXP__ (-382) 
#define __DEC64_MIN__ 1E-383DD 
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD 
#define __DECIMAL_DIG__ 17 
#define __DEC_EVAL_METHOD__ 2 
#define __ELF__ 1 
#define __FINITE_MATH_ONLY__ 0 
#define __FLOAT_WORD_ORDER__ __ORDER_LITTLE_ENDIAN__ 
#define __FLT_DECIMAL_DIG__ 9 
#define __FLT_DENORM_MIN__ 1.4012984643248171e-45F 
#define __FLT_DIG__ 6 
#define __FLT_EPSILON__ 1.1920928955078125e-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__ 3.4028234663852886e+38F 
#define __FLT_MIN_10_EXP__ (-37) 
#define __FLT_MIN_EXP__ (-125) 
#define __FLT_MIN__ 1.1754943508222875e-38F 
#define __FLT_RADIX__ 2 
#define __GNUC_GNU_INLINE__ 1 
#define __GNUC_MINOR__ 6 
#define __GNUC_PATCHLEVEL__ 0 
#define __GNUC__ 4 
#define __GXX_ABI_VERSION 1002 
#define __GXX_TYPEINFO_EQUALITY_INLINE 0 
#define __INT16_C(c) c 
#define __INT16_MAX__ 32767 
#define __INT16_TYPE__ short int 
#define __INT32_C(c) c 
#define __INT32_MAX__ 2147483647 
#define __INT32_TYPE__ int 
#define __INT64_C(c) C## LL 
#define __INT64_MAX__ 9223372036854775807LL 
#define __INT64_TYPE__ long long int 
#define __INT8_C(c) c 
#define __INT8_MAX__ 127 
#define __INT8_TYPE__ signed char 
#define __INTMAX_C(c) C## LL 
#define __INTMAX_MAX__ 9223372036854775807LL 
#define __INTMAX_TYPE__ long long int 
#define __INTPTR_MAX__ 2147483647 
#define __INTPTR_TYPE__ int 
#define __INT_FAST16_MAX__ 2147483647 
#define __INT_FAST16_TYPE__ int 
#define __INT_FAST32_MAX__ 2147483647 
#define __INT_FAST32_TYPE__ int 
#define __INT_FAST64_MAX__ 9223372036854775807LL 
#define __INT_FAST64_TYPE__ long long int 
#define __INT_FAST8_MAX__ 127 
#define __INT_FAST8_TYPE__ signed char 
#define __INT_LEAST16_MAX__ 32767 
#define __INT_LEAST16_TYPE__ short int 
#define __INT_LEAST32_MAX__ 2147483647 
#define __INT_LEAST32_TYPE__ int 
#define __INT_LEAST64_MAX__ 9223372036854775807LL 
#define __INT_LEAST64_TYPE__ long long int 
#define __INT_LEAST8_MAX__ 127 
#define __INT_LEAST8_TYPE__ signed char 
#define __INT_MAX__ 2147483647 
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L 
#define __LDBL_DIG__ 15 
#define __LDBL_EPSILON__ 2.2204460492503131e-16L 
#define __LDBL_HAS_DENORM__ 1 
#define __LDBL_HAS_INFINITY__ 1 
#define __LDBL_HAS_QUIET_NAN__ 1 
#define __LDBL_MANT_DIG__ 53 
#define __LDBL_MAX_10_EXP__ 308 
#define __LDBL_MAX_EXP__ 1024 
#define __LDBL_MAX__ 1.7976931348623157e+308L 
#define __LDBL_MIN_10_EXP__ (-307) 
#define __LDBL_MIN_EXP__ (-1021) 
#define __LDBL_MIN__ 2.2250738585072014e-308L 
#define __LONG_LONG_MAX__ 9223372036854775807LL 
#define __LONG_MAX__ 2147483647L 
#define __NO_INLINE__ 1 
#define __ORDER_BIG_ENDIAN__ 4321 
#define __ORDER_LITTLE_ENDIAN__ 1234 
#define __ORDER_PDP_ENDIAN__ 3412 
#define __PIC__ 1 
#define __PRAGMA_REDEFINE_EXTNAME 1 
#define __PTRDIFF_MAX__ 2147483647 
#define __PTRDIFF_TYPE__ int 
#define __REGISTER_PREFIX__ 
#define __SCHAR_MAX__ 127 
#define __SHRT_MAX__ 32767 
#define __SIG_ATOMIC_MAX__ 2147483647 
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1) 
#define __SIG_ATOMIC_TYPE__ int 
#define __SIZEOF_DOUBLE__ 8 
#define __SIZEOF_FLOAT__ 4 
#define __SIZEOF_INT__ 4 
#define __SIZEOF_LONG_DOUBLE__ 8 
#define __SIZEOF_LONG_LONG__ 8 
#define __SIZEOF_LONG__ 4 
#define __SIZEOF_POINTER__ 4 
#define __SIZEOF_PTRDIFF_T__ 4 
#define __SIZEOF_SHORT__ 2 
#define __SIZEOF_SIZE_T__ 4 
#define __SIZEOF_WCHAR_T__ 4 
#define __SIZEOF_WINT_T__ 4 
#define __SIZE_MAX__ 4294967295U 
#define __SIZE_TYPE__ unsigned int 
#define __SOFTFP__ 1 
#define __STDC_HOSTED__ 1 
#define __STDC__ 1 
#define __THUMB_INTERWORK__ 1 
#define __UINT16_C(c) c 
#define __UINT16_MAX__ 65535 
#define __UINT16_TYPE__ short unsigned int 
#define __UINT32_C(c) C## U 
#define __UINT32_MAX__ 4294967295U 
#define __UINT32_TYPE__ unsigned int 
#define __UINT64_C(c) C## ULL 
#define __UINT64_MAX__ 18446744073709551615ULL 
#define __UINT64_TYPE__ long long unsigned int 
#define __UINT8_C(c) c 
#define __UINT8_MAX__ 255 
#define __UINT8_TYPE__ unsigned char 
#define __UINTMAX_C(c) C## ULL 
#define __UINTMAX_MAX__ 18446744073709551615ULL 
#define __UINTMAX_TYPE__ long long unsigned int 
#define __UINTPTR_MAX__ 4294967295U 
#define __UINTPTR_TYPE__ unsigned int 
#define __UINT_FAST16_MAX__ 4294967295U 
#define __UINT_FAST16_TYPE__ unsigned int 
#define __UINT_FAST32_MAX__ 4294967295U 
#define __UINT_FAST32_TYPE__ unsigned int 
#define __UINT_FAST64_MAX__ 18446744073709551615ULL 
#define __UINT_FAST64_TYPE__ long long unsigned int 
#define __UINT_FAST8_MAX__ 255 
#define __UINT_FAST8_TYPE__ unsigned char 
#define __UINT_LEAST16_MAX__ 65535 
#define __UINT_LEAST16_TYPE__ short unsigned int 
#define __UINT_LEAST32_MAX__ 4294967295U 
#define __UINT_LEAST32_TYPE__ unsigned int 
#define __UINT_LEAST64_MAX__ 18446744073709551615ULL 
#define __UINT_LEAST64_TYPE__ long long unsigned int 
#define __UINT_LEAST8_MAX__ 255 
#define __UINT_LEAST8_TYPE__ unsigned char 
#define __USER_LABEL_PREFIX__ 
#define __VERSION__ "4.6 20120106 (prerelease)" 
#define __VFP_FP__ 1 
#define __WCHAR_MAX__ 4294967295U 
#define __WCHAR_MIN__ 0U 
#define __WCHAR_TYPE__ unsigned int 
#define __WINT_MAX__ 4294967295U 
#define __WINT_MIN__ 0U 
#define __WINT_TYPE__ unsigned int 
#define __arm__ 1 
#define __linux 1 
#define __linux__ 1 
#define __pic__ 1 
#define __unix 1 
#define __unix__ 1 
#define linux 1 
#define unix 1