今天用MinGW()编译一个项目，怎么也想不起来用哪一个宏来判断用的是mingw的gcc编译器，不得以只好在头文件中搜索，找了半天终于发现是：__MINGW32__。
后来我就想，有没有一个办法能把编译器的所有预定义宏列出来呢？于是左google右google，终于让我用“mingw predefined macro”这几个关键字打出了解决方案：
- 先定义一个最简单的C文件（其实任何C文件都可以），只有一行：
int main(void) {}
gcc -dM -E test.c
编译器会列出所有的预定义宏，如下：
#define __DBL_MIN_EXP__ (-1021)
#define __FLT_MIN__ 1.17549435e-38F
#define _WIN32 1
#define __CHAR_BIT__ 8
#define __WCHAR_MAX__ 65535U
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __FLT__METHOD__ 2
#define __DBL_MIN_10_EXP__ (-307)
#define __FINITE_MATH_ONLY__ 0
#define __GNUC_PATCHLEVEL__ 0
#define _stdcall __attribute__((__stdcall__))
#define __DEC64_MAX_EXP__ 385
#define __SHRT_MAX__ 32767
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __GXX_TYPEINFO_EQUALITY_INLINE 0
#define __UINTMAX_TYPE__ long long unsigned int
#define __DEC32_EPSILON__ 1E-6DF
#define __LDBL_MAX_EXP__ 16384
#define __SCHAR_MAX__ 127
#define __DBL_DIG__ 15
#define __SIZEOF_INT__ 4
#define __SIZEOF_POINTER__ 4
#define __USER_LABEL_PREFIX__ _
#define __STDC_HOSTED__ 1
#define __WIN32 1
#define __LDBL_HAS_INFINITY__ 1
#define __FLT_EPSILON__ 1.19209290e-7F
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __DEC32_MAX__ 9.999999E96DF
#define
__MINGW32__ 1
。。。
当然，你也可以换成你想查看的编译器，如android的编译器：
arm-eabi-gcc
-dM -E test.c则Android的Toolchain编译器的所有预定义宏显示如下：
#define __DBL_MIN_EXP__ (-1021)
#define __FLT_MIN__ 1.17549435e-38F
#define __DEC64_DEN__ 0.000000000000001E-383DD
#define __CHAR_BIT__ 8
#define __WCHAR_MAX__ 4294967295U
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __FLT__METHOD__ 0
#define __DBL_MIN_10_EXP__ (-307)
#define __FINITE_MATH_ONLY__ 0
#define __ARMEL__ 1
#define __GNUC_PATCHLEVEL__ 1
#define __DEC64_MAX_EXP__ 384
#define __SHRT_MAX__ 32767
#define __LDBL_MAX__ 1.7976931348623157e+308L
#define __UINTMAX_TYPE__ long long unsigned int
#define __DEC32_EPSILON__ 1E-6DF
#define __CHAR_UNSIGNED__ 1
#define __LDBL_MAX_EXP__ 1024
#define __SCHAR_MAX__ 127
#define __DBL_DIG__ 15
#define __USER_LABEL_PREFIX__
#define __STDC_HOSTED__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __FLT_EPSILON__ 1.19209290e-7F
#define __APCS_32__ 1
#define __LDBL_MIN__ 2.2250738585072014e-308L
#define __DEC32_MAX__ 9.999999E96DF
#define __DECIMAL_DIG__ 17
#define __LDBL_HAS_QUIET_NAN__ 1
#define
__GNUC__ 4
#define __FLT_HAS_DENORM__ 1
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_HAS_INFINITY__ 1
#define __DEC32_MIN_EXP__ (-95)
#define
__THUMB_INTERWORK__ 1
#define __LDBL_HAS_DENORM__ 1
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL
#define __DEC32_MIN__ 1E-95DF
#define __DBL_MAX_EXP__ 1024
#define __DEC128_EPSILON__ 1E-33DL
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __GXX_ABI_VERSION 1002
#define
__SOFTFP__ 1
#define __FLT_MIN_EXP__ (-125)
#define __DBL_MIN__ 2.2250738585072014e-308
#define __USES_INITFINI__ 1
#define __DEC128_MIN__ 1E-6143DL
#define __REGISTER_PREFIX__
#define __DBL_HAS_DENORM__ 1
#define
__NO_INLINE__ 1
#define __FLT_MANT_DIG__ 24
#define __VERSION__ "4.2.1"
#define __DEC64_EPSILON__ 1E-15DD
#define __DEC128_MIN_EXP__ (-6143)
#define __SIZE_TYPE__ unsigned int
#define __DEC32_DEN__ 0.000001E-95DF
#define
__ELF__ 1
#define __FLT_RADIX__ 2
#define __LDBL_EPSILON__ 2.2204460492503131e-16L
#define __VFP_FP__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MAX_10_EXP__ 38
#define __LONG_MAX__ 2147483647L
#define __FLT_HAS_INFINITY__ 1
#define __DEC64_MAX__ 9.999999999999999E384DD
#define __DEC64_MANT_DIG__ 16
#define __DEC32_MAX_EXP__ 96
#define __DEC128_DEN__ 0.000000000000000000000000000000001E-6143DL
#define __GXX_MERGED_TYPEINFO_NAMES 0
#define __LDBL_MANT_DIG__ 53
#define __DBL_HAS_QUIET_NAN__ 1
#define __WCHAR_TYPE__ unsigned int
#define __DEC64_MIN_EXP__ (-383)
#define __FLT_DIG__ 6
#define __INT_MAX__ 2147483647
#define __FLT_MAX_EXP__ 128
#define __DBL_MANT_DIG__ 53
#define __DEC64_MIN__ 1E-383DD
#define __WINT_TYPE__ unsigned int
#define __LDBL_MIN_EXP__ (-1021)
#define
__arm__ 1
#define __LDBL_MAX_10_EXP__ 308
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DEC__METHOD__ 2
#define __INTMAX_MAX__ 9223372036854775807LL
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __INTMAX_TYPE__ long long int
#define __DEC128_MAX_EXP__ 6144
#define __GNUC_MINOR__ 2
#define __DEC32_MANT_DIG__ 7
#define __DBL_MAX_10_EXP__ 308
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
#define
__STDC__ 1
#define
__ARM_ARCH_4T__ 1
#define __PTRDIFF_TYPE__ int
#define
__ARM_EABI__ 1
#define __DEC128_MANT_DIG__ 34
#define __LDBL_MIN_10_EXP__ (-307)
#define __LDBL_DIG__ 15
#define __GNUC_GNU_INLINE__ 1
