Here is a list of preprocessor defined macros when compiling in Xcode.

Xcode defines a few other macros as well, if anyone knows how to get those to output please share!

So useful!

**terminal:$ gcc -dM -E - < /dev/null**

#define __DBL_MIN_EXP__ (-1021)

#define __FLT_MIN__ 1.17549435e-38F

#define __DEC64_DEN__ 0.000000000000001E-383DD

#define __CHAR_BIT__ 8

#define __WCHAR_MAX__ 2147483647

#define __DBL_DENORM_MIN__ 4.9406564584124654e-324

#define __FLT_EVAL_METHOD__ 0

#define __DBL_MIN_10_EXP__ (-307)

#define __FINITE_MATH_ONLY__ 0

#define __DEC64_MAX_EXP__ 384

#define __SHRT_MAX__ 32767

#define __LDBL_MAX__ 1.18973149535723176502e+4932L

#define __APPLE_CC__ 5664

#define __UINTMAX_TYPE__ long unsigned int

#define __DEC32_EPSILON__ 1E-6DF

#define __block __attribute__((__blocks__(byref)))

#define __SCHAR_MAX__ 127

#define __USER_LABEL_PREFIX__ _

#define __STDC_HOSTED__ 1

#define __DEC64_MIN_EXP__ (-383)

#define __DBL_DIG__ 15

#define __FLT_EPSILON__ 1.19209290e-7F

#define __LDBL_MIN__ 3.36210314311209350626e-4932L

#define __DEC32_MAX__ 9.999999E96DF

#define __strong

#define __APPLE__ 1

#define __DECIMAL_DIG__ 21

#define __LDBL_HAS_QUIET_NAN__ 1

#define __DYNAMIC__ 1

#define __GNUC__ 4

#define __MMX__ 1

#define __FLT_HAS_DENORM__ 1

#define __DBL_MAX__ 1.7976931348623157e+308

#define __DBL_HAS_INFINITY__ 1

#define __DEC32_MIN_EXP__ (-95)

#define OBJC_NEW_PROPERTIES 1

#define __LDBL_HAS_DENORM__ 1

#define __DEC32_MIN__ 1E-95DF

#define __weak __attribute__((objc_gc(weak)))

#define __DBL_MAX_EXP__ 1024

#define __DEC128_EPSILON__ 1E-33DL

#define __SSE2_MATH__ 1

#define __amd64 1

#define __tune_core2__ 1

#define __LONG_LONG_MAX__ 9223372036854775807LL

#define __GXX_ABI_VERSION 1002

#define __FLT_MIN_EXP__ (-125)

#define __x86_64 1

#define __DBL_MIN__ 2.2250738585072014e-308

#define __LP64__ 1

#define __DBL_HAS_QUIET_NAN__ 1

#define __DEC128_MIN__ 1E-6143DL

#define __REGISTER_PREFIX__

#define __DBL_HAS_DENORM__ 1

#define __NO_INLINE__ 1

#define __DEC_EVAL_METHOD__ 2

#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL

#define __FLT_MANT_DIG__ 24

#define __VERSION__ "4.2.1 (Apple Inc. build 5664)"

#define __DEC64_EPSILON__ 1E-15DD

#define __DEC128_MIN_EXP__ (-6143)

#define __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ 1066

#define __SIZE_TYPE__ long unsigned int

#define __DEC32_DEN__ 0.000001E-95DF

#define __FLT_RADIX__ 2

#define __LDBL_EPSILON__ 1.08420217248550443401e-19L

#define __SSE_MATH__ 1

#define __k8 1

#define __LDBL_DIG__ 18

#define __x86_64__ 1

#define __FLT_HAS_QUIET_NAN__ 1

#define __FLT_MAX_10_EXP__ 38

#define __LONG_MAX__ 9223372036854775807L

#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 __LITTLE_ENDIAN__ 1

#define __LDBL_MANT_DIG__ 64

#define __CONSTANT_CFSTRINGS__ 1

#define __DEC32_MANT_DIG__ 7

#define __k8__ 1

#define __WCHAR_TYPE__ int

#define __pic__ 2

#define __FLT_DIG__ 6

#define __INT_MAX__ 2147483647

#define __FLT_MAX_EXP__ 128

#define __BLOCKS__ 1

#define __DBL_MANT_DIG__ 53

#define __DEC64_MIN__ 1E-383DD

#define __WINT_TYPE__ int

#define __SSE__ 1

#define __LDBL_MIN_EXP__ (-16381)

#define __MACH__ 1

#define __amd64__ 1

#define __LDBL_MAX_EXP__ 16384

#define __SSP__ 1

#define __LDBL_MAX_10_EXP__ 4932

#define __DBL_EPSILON__ 2.2204460492503131e-16

#define _LP64 1

#define __GNUC_PATCHLEVEL__ 1

#define __LDBL_HAS_INFINITY__ 1

#define __INTMAX_MAX__ 9223372036854775807L

#define __FLT_DENORM_MIN__ 1.40129846e-45F

#define __PIC__ 2

#define __FLT_MAX__ 3.40282347e+38F

#define __SSE2__ 1

#define __FLT_MIN_10_EXP__ (-37)

#define __INTMAX_TYPE__ long int

#define __DEC128_MAX_EXP__ 6144

#define __GNUC_MINOR__ 2

#define __DBL_MAX_10_EXP__ 308

#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L

#define __STDC__ 1

#define __PTRDIFF_TYPE__ long int

#define __DEC128_MANT_DIG__ 34

#define __LDBL_MIN_10_EXP__ (-4931)

#define __GNUC_GNU_INLINE__ 1

#define __SSE3__ 1

```
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