I am trying to figure out how the integer type definitions from various header files are related to each other.
I just installed the CygWin. I opened the Cygwin\x86\usr\include\machine\_default_types.h. In it I noticed below code snippets:
#ifdef __INT8_TYPE__
typedef __INT8_TYPE__ __int8_t;
According to here, the __INT8_TYPE__ is one of the predefined pre-processor macros. And:
You should not use these macros directly; instead, include the
appropriate headers and use the typedefs. Some of these macros may not
be defined on particular systems if GCC does not provide a stdint.h
header on those systems.
So it seems the __INT8_TYPE__ should be defined somewhere else. But I searched the whole CygWin installation, there's no definition for it. All I found are some conditional statements just like above one.
Since I shouldn't use it directly. And no other files are defining it. How could this macro ever come into action? Or did I misunderstand something?
This is a predefined macro. To see them you can:
gcc -dM -E - < /dev/null
e.g.:
$ gcc -dM -E - < /dev/null | grep __INT
#define __INTMAX_C(c) c ## L
#define __INT8_C(c) c
#define __INT64_C(c) c ## L
#define __INT32_MAX__ 0x7fffffff
#define __INT_FAST32_MAX__ 0x7fffffffffffffffL
#define __INT_FAST16_TYPE__ long int
#define __INT_LEAST32_MAX__ 0x7fffffff
#define __INT_FAST64_TYPE__ long int
#define __INT32_C(c) c
#define __INT_FAST32_TYPE__ long int
#define __INT16_MAX__ 0x7fff
#define __INT8_TYPE__ signed char
#define __INT_LEAST16_TYPE__ short int
#define __INT_FAST16_MAX__ 0x7fffffffffffffffL
#define __INT_LEAST16_MAX__ 0x7fff
#define __INT64_MAX__ 0x7fffffffffffffffL
#define __INT_LEAST64_TYPE__ long int
#define __INT16_TYPE__ short int
#define __INT_LEAST8_TYPE__ signed char
#define __INT_FAST8_MAX__ 0x7f
#define __INTPTR_MAX__ 0x7fffffffffffffffL
#define __INTPTR_TYPE__ long int
#define __INT_FAST64_MAX__ 0x7fffffffffffffffL
#define __INT_MAX__ 0x7fffffff
#define __INT64_TYPE__ long int
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffL
#define __INT_LEAST8_MAX__ 0x7f
#define __INT_LEAST32_TYPE__ int
#define __INT_FAST8_TYPE__ signed char
#define __INTMAX_MAX__ 0x7fffffffffffffffL
#define __INT8_MAX__ 0x7f
#define __INT32_TYPE__ int
#define __INTMAX_TYPE__ long int
#define __INT16_C(c) c
Related
I'm trying to write definitions for AVR C code so that i can access pins by simmple macro like
STATUS_LED_OUT =1;
in GENET_HW_DEF.h file, included to main C file. You can reproduce this bug by including this file into any C project.
I'm using avr studio 6.2 and 7 - both give the same result. I cannot compile getting werid macro unfold message like below. (CPU ATMega1284p)
D:\_SVN\Compass\AVR\Compass_IO_proto\Compass IO_proto\GENET_HW_DEF.h(19,49): error: expected ')' before '&' token
#define REGISTER_BIT(rg,bt) ((volatile _io_reg*)&rg)->bit##bt
^
D:\_SVN\Compass\AVR\Compass_IO_proto\Compass IO_proto\GENET_HW_DEF.h(42,25): info: in expansion of macro 'REGISTER_BIT'
#define STATUS_LED_OUT REGISTER_BIT(PORTB,7)
^
D:\_SVN\Compass\AVR\Compass_IO_proto\Compass IO_proto\GENET_HW_DEF.h(46,2): info: in expansion of macro 'STATUS_LED_OUT'
STATUS_LED_OUT=1;
^
Interesting enough, copied to fresh project with just only one or two declarations compiles fine, until one makes any changes in the declarations - like adding another macro reference. Then it becomes stuck again.
Also - if i comment all macro usages like
STATUS_LED_DIR=1;
STATUS_LED_OUT=1;
then I'm able to compile project and then after uncommenting usage lines it still compiles fine.. untill clean is executed. I'm probably messing with macro quirks but I have no idea where.
typedef struct
{
unsigned int bit0:1;
unsigned int bit1:1;
unsigned int bit2:1;
unsigned int bit3:1;
unsigned int bit4:1;
unsigned int bit5:1;
unsigned int bit6:1;
unsigned int bit7:1;
} _io_reg;
#define REGISTER_BIT(rg,bt) ((volatile _io_reg*)&rg)->bit##bt
#ifndef GENET_HW_DEF
#define GENET_HW_DEF
// define functionalities and flags - comment/uncomment apropriate lines
#define GENET_USART_0 256
#define GENET_USART_1 256
#define F_CPU 20000000UL
#define STATUS_LED 7
#define ERROR_LED 4
#define ADC_GLOBAL_ENABLE A
#define ADC_CHANNEL_0 0
#define ADC_CHANNEL_1 4
#define ADC_CHANNEL_2 2
#define ADC_CHANNEL_3 3
#define ADC_CHANNEL_4 1
#define ADC_CHANNEL_5 5
#define ADC_CHANNEL_6 6
#define ADC_CHANNEL_7 7
// actual definitions and initialization
#ifdef STATUS_LED
#define STATUS_LED_OUT REGISTER_BIT(PORTB,STATUS_LED)
#define STATUS_LED_DIR REGISTER_BIT(DDRB,STATUS_LED)
#define STATUS_LED_PIN REGISTER_BIT(PINB,STATUS_LED)
STATUS_LED_DIR=1;
STATUS_LED_OUT=1;
#endif
#ifdef ERROR_LED
#define ERROR_LED_OUT REGISTER_BIT(PORTC,ERROR_LED)
#define ERROR_LED_DIR REGISTER_BIT(DDRC,ERROR_LED)
ERROR_LED_DIR=1;
ERROR_LED_OUT=1;
#endif
#ifdef GENET_USART_0
#define USART0_ENABLED
#define UART_RX0_BUFFER_SIZE GENET_USART_0
#define UART_TX0_BUFFER_SIZE GENET_USART_0
#endif
#ifdef GENET_USART_1
#define USART1_ENABLED
#define UART_RX1_BUFFER_SIZE GENET_USART_1
#define UART_TX1_BUFFER_SIZE GENET_USART_1
#endif
#endif
I reproduced your problem.
You cannot call STATUS_LED_DIR=1; outside code execution flow. This must be inside a function (for example main()).
Now you will end with other compilation errors but this was the main mistake.
Second correction, you need 2 level for concatenation
#define CONCAT(bt) bit##bt
#define REGISTER_BIT(rg,bt) ((volatile _io_reg*)&rg)->CONCAT(bt)
Why does the C preprocessor in GCC interpret the word linux (small letters) as the constant 1?
test.c:
#include <stdio.h>
int main(void)
{
int linux = 5;
return 0;
}
Result of $ gcc -E test.c (stop after the preprocessing stage):
....
int main(void)
{
int 1 = 5;
return 0;
}
Which of course yields an error.
(BTW: There is no #define linux in the stdio.h file.)
In the Old Days (pre-ANSI), predefining symbols such as unix and vax was a way to allow code to detect at compile time what system it was being compiled for. There was no official language standard back then (beyond the reference material at the back of the first edition of K&R), and C code of any complexity was typically a complex maze of #ifdefs to allow for differences between systems. These macro definitions were generally set by the compiler itself, not defined in a library header file. Since there were no real rules about which identifiers could be used by the implementation and which were reserved for programmers, compiler writers felt free to use simple names like unix and assumed that programmers would simply avoid using those names for their own purposes.
The 1989 ANSI C standard introduced rules restricting what symbols an implementation could legally predefine. A macro predefined by the compiler could only have a name starting with two underscores, or with an underscore followed by an uppercase letter, leaving programmers free to use identifiers not matching that pattern and not used in the standard library.
As a result, any compiler that predefines unix or linux is non-conforming, since it will fail to compile perfectly legal code that uses something like int linux = 5;.
As it happens, gcc is non-conforming by default -- but it can be made to conform (reasonably well) with the right command-line options:
gcc -std=c90 -pedantic ... # or -std=c89 or -ansi
gcc -std=c99 -pedantic
gcc -std=c11 -pedantic
See the gcc manual for more details.
gcc will be phasing out these definitions in future releases, so you shouldn't write code that depends on them. If your program needs to know whether it's being compiled for a Linux target or not it can check whether __linux__ is defined (assuming you're using gcc or a compiler that's compatible with it). See the GNU C preprocessor manual for more information.
A largely irrelevant aside: the "Best One Liner" winner of the 1987 International Obfuscated C Code Contest, by David Korn (yes, the author of the Korn Shell) took advantage of the predefined unix macro:
main() { printf(&unix["\021%six\012\0"],(unix)["have"]+"fun"-0x60);}
It prints "unix", but for reasons that have absolutely nothing to do with the spelling of the macro name.
I don't want to post any spoilers here, and I encourage anyone reading this to try to understand that code on their own first. But if you really want to give up, I've posted an explanation here:
https://gist.github.com/Keith-S-Thompson/6920347
This appears to be an (undocumented) "GNU extension": [correction: I finally found a mention in the docs. See below.]
The following command uses the -dM option to print all preprocessor defines; since the input "file" is empty, it shows exactly the predefined macros. It was run with gcc-4.7.3 on a standard ubuntu install. You can see that the preprocessor is standard-aware. In total, there 243 macros with -std=gnu99 and 240 with -std=c99; I filtered the output for relevance.
$ cpp --std=c89 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
$ cpp --std=gnu89 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
#define linux 1
$ cpp --std=c99 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
$ cpp --std=gnu99 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
#define linux 1
The "gnu standard" versions also #define unix. (Using c11 and gnu11 produces the same results.)
I suppose they had their reasons, but it seems to me to make the default installation of gcc (which compiles C code with -std=gnu89 unless otherwise specified) non-conformant, and -- as in this question -- surprising. Polluting the global namespace with macros whose names don't begin with an underscore is not permitted in a conformant implementation. (6.8.10p2: "Any other predefined macro names shall begin with a leading underscore followed by an uppercase letter or a second
underscore," but, as mentioned in Appendix J.5 (portability issues), such names are often predefined.)
When I originally wrote this answer, I wasn't able to find any documentation in gcc about this issue, but I did finally discover it, not in C implementation-defined behaviour nor in C extensions but in the cpp manual section 3.7.3, where it notes that:
We are slowly phasing out all predefined macros which are outside the reserved namespace. You should never use them in new programs…
Because linux is a built-in macro defined when the compiler is running on, or compiling for (if it is a cross-compiler), Linux.
There are a lot of such predefined macros. With GCC, you can use:
cp /dev/null emptyfile.c
gcc -E -dM emptyfile.c
to get a list of macros. (I've not managed to persuade GCC to accept /dev/null directly, but
the empty file seems to work OK.) With GCC 4.8.1 running on Mac OS X 10.8.5, I got the output:
#define __DBL_MIN_EXP__ (-1021)
#define __UINT_LEAST16_MAX__ 65535
#define __ATOMIC_ACQUIRE 2
#define __FLT_MIN__ 1.17549435082228750797e-38F
#define __UINT_LEAST8_TYPE__ unsigned char
#define __INTMAX_C(c) c ## L
#define __CHAR_BIT__ 8
#define __UINT8_MAX__ 255
#define __WINT_MAX__ 2147483647
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __SIZE_MAX__ 18446744073709551615UL
#define __WCHAR_MAX__ 2147483647
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L)
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __FLT_EVAL_METHOD__ 0
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __x86_64 1
#define __UINT_FAST64_MAX__ 18446744073709551615ULL
#define __SIG_ATOMIC_TYPE__ int
#define __DBL_MIN_10_EXP__ (-307)
#define __FINITE_MATH_ONLY__ 0
#define __GNUC_PATCHLEVEL__ 1
#define __UINT_FAST8_MAX__ 255
#define __DEC64_MAX_EXP__ 385
#define __INT8_C(c) c
#define __UINT_LEAST64_MAX__ 18446744073709551615ULL
#define __SHRT_MAX__ 32767
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __UINT_LEAST8_MAX__ 255
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __APPLE_CC__ 1
#define __UINTMAX_TYPE__ long unsigned int
#define __DEC32_EPSILON__ 1E-6DF
#define __UINT32_MAX__ 4294967295U
#define __LDBL_MAX_EXP__ 16384
#define __WINT_MIN__ (-__WINT_MAX__ - 1)
#define __SCHAR_MAX__ 127
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
#define __INT64_C(c) c ## LL
#define __DBL_DIG__ 15
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __SIZEOF_INT__ 4
#define __SIZEOF_POINTER__ 8
#define __USER_LABEL_PREFIX__ _
#define __STDC_HOSTED__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __FLT_EPSILON__ 1.19209289550781250000e-7F
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __DEC32_MAX__ 9.999999E96DF
#define __strong
#define __INT32_MAX__ 2147483647
#define __SIZEOF_LONG__ 8
#define __APPLE__ 1
#define __UINT16_C(c) c
#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 __SIZEOF_LONG_DOUBLE__ 16
#define __BIGGEST_ALIGNMENT__ 16
#define __DBL_MAX__ ((double)1.79769313486231570815e+308L)
#define __INT_FAST32_MAX__ 2147483647
#define __DBL_HAS_INFINITY__ 1
#define __DEC32_MIN_EXP__ (-94)
#define __INT_FAST16_TYPE__ short int
#define __LDBL_HAS_DENORM__ 1
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL
#define __INT_LEAST32_MAX__ 2147483647
#define __DEC32_MIN__ 1E-95DF
#define __weak
#define __DBL_MAX_EXP__ 1024
#define __DEC128_EPSILON__ 1E-33DL
#define __SSE2_MATH__ 1
#define __ATOMIC_HLE_RELEASE 131072
#define __PTRDIFF_MAX__ 9223372036854775807L
#define __amd64 1
#define __tune_core2__ 1
#define __ATOMIC_HLE_ACQUIRE 65536
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __SIZEOF_SIZE_T__ 8
#define __SIZEOF_WINT_T__ 4
#define __GXX_ABI_VERSION 1002
#define __FLT_MIN_EXP__ (-125)
#define __INT_FAST64_TYPE__ long long int
#define __DBL_MIN__ ((double)2.22507385850720138309e-308L)
#define __LP64__ 1
#define __DEC128_MIN__ 1E-6143DL
#define __REGISTER_PREFIX__
#define __UINT16_MAX__ 65535
#define __DBL_HAS_DENORM__ 1
#define __UINT8_TYPE__ unsigned char
#define __NO_INLINE__ 1
#define __FLT_MANT_DIG__ 24
#define __VERSION__ "4.8.1"
#define __UINT64_C(c) c ## ULL
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __FLOAT_WORD_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __INT32_C(c) c
#define __DEC64_EPSILON__ 1E-15DD
#define __ORDER_PDP_ENDIAN__ 3412
#define __DEC128_MIN_EXP__ (-6142)
#define __INT_FAST32_TYPE__ int
#define __UINT_LEAST16_TYPE__ short unsigned int
#define __INT16_MAX__ 32767
#define __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ 1080
#define __SIZE_TYPE__ long unsigned int
#define __UINT64_MAX__ 18446744073709551615ULL
#define __INT8_TYPE__ signed char
#define __FLT_RADIX__ 2
#define __INT_LEAST16_TYPE__ short int
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __UINTMAX_C(c) c ## UL
#define __SSE_MATH__ 1
#define __k8 1
#define __SIG_ATOMIC_MAX__ 2147483647
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __SIZEOF_PTRDIFF_T__ 8
#define __x86_64__ 1
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF
#define __INT_FAST16_MAX__ 32767
#define __UINT_FAST32_MAX__ 4294967295U
#define __UINT_LEAST64_TYPE__ long long unsigned int
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MAX_10_EXP__ 38
#define __LONG_MAX__ 9223372036854775807L
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL
#define __FLT_HAS_INFINITY__ 1
#define __UINT_FAST16_TYPE__ short unsigned int
#define __DEC64_MAX__ 9.999999999999999E384DD
#define __CHAR16_TYPE__ short unsigned int
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __INT_LEAST16_MAX__ 32767
#define __DEC64_MANT_DIG__ 16
#define __INT64_MAX__ 9223372036854775807LL
#define __UINT_LEAST32_MAX__ 4294967295U
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __INT_LEAST64_TYPE__ long long int
#define __INT16_TYPE__ short int
#define __INT_LEAST8_TYPE__ signed char
#define __DEC32_MAX_EXP__ 97
#define __INT_FAST8_MAX__ 127
#define __INTPTR_MAX__ 9223372036854775807L
#define __LITTLE_ENDIAN__ 1
#define __SSE2__ 1
#define __LDBL_MANT_DIG__ 64
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __code_model_small__ 1
#define __k8__ 1
#define __INTPTR_TYPE__ long int
#define __UINT16_TYPE__ short unsigned int
#define __WCHAR_TYPE__ int
#define __SIZEOF_FLOAT__ 4
#define __pic__ 2
#define __UINTPTR_MAX__ 18446744073709551615UL
#define __DEC64_MIN_EXP__ (-382)
#define __INT_FAST64_MAX__ 9223372036854775807LL
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __FLT_DIG__ 6
#define __UINT_FAST64_TYPE__ long long unsigned int
#define __INT_MAX__ 2147483647
#define __MACH__ 1
#define __amd64__ 1
#define __INT64_TYPE__ long long int
#define __FLT_MAX_EXP__ 128
#define __ORDER_BIG_ENDIAN__ 4321
#define __DBL_MANT_DIG__ 53
#define __INT_LEAST64_MAX__ 9223372036854775807LL
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __DEC64_MIN__ 1E-383DD
#define __WINT_TYPE__ int
#define __UINT_LEAST32_TYPE__ unsigned int
#define __SIZEOF_SHORT__ 2
#define __SSE__ 1
#define __LDBL_MIN_EXP__ (-16381)
#define __INT_LEAST8_MAX__ 127
#define __SIZEOF_INT128__ 16
#define __LDBL_MAX_10_EXP__ 4932
#define __ATOMIC_RELAXED 0
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-16L)
#define _LP64 1
#define __UINT8_C(c) c
#define __INT_LEAST32_TYPE__ int
#define __SIZEOF_WCHAR_T__ 4
#define __UINT64_TYPE__ long long unsigned int
#define __INT_FAST8_TYPE__ signed char
#define __DBL_DECIMAL_DIG__ 17
#define __FXSR__ 1
#define __DEC_EVAL_METHOD__ 2
#define __UINT32_C(c) c ## U
#define __INTMAX_MAX__ 9223372036854775807L
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
#define __INT8_MAX__ 127
#define __PIC__ 2
#define __UINT_FAST32_TYPE__ unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __FLT_MAX__ 3.40282346638528859812e+38F
#define __INT32_TYPE__ int
#define __SIZEOF_DOUBLE__ 8
#define __FLT_MIN_10_EXP__ (-37)
#define __INTMAX_TYPE__ long int
#define __DEC128_MAX_EXP__ 6145
#define __ATOMIC_CONSUME 1
#define __GNUC_MINOR__ 8
#define __UINTMAX_MAX__ 18446744073709551615UL
#define __DEC32_MANT_DIG__ 7
#define __DBL_MAX_10_EXP__ 308
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __INT16_C(c) c
#define __STDC__ 1
#define __PTRDIFF_TYPE__ long int
#define __ATOMIC_SEQ_CST 5
#define __UINT32_TYPE__ unsigned int
#define __UINTPTR_TYPE__ long unsigned int
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD
#define __DEC128_MANT_DIG__ 34
#define __LDBL_MIN_10_EXP__ (-4931)
#define __SIZEOF_LONG_LONG__ 8
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __LDBL_DIG__ 18
#define __FLT_DECIMAL_DIG__ 9
#define __UINT_FAST16_MAX__ 65535
#define __GNUC_GNU_INLINE__ 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __SSE3__ 1
#define __UINT_FAST8_TYPE__ unsigned char
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3
That's 236 macros from an empty file. When I added #include <stdio.h> to the file, the number of macros defined went up to 505. These includes all sorts of platform-identifying macros.
From info gcc (emphasis mine):
-ansi
In C mode, this is equivalent to -std=c90. In C++ mode, it is
equivalent to -std=c++98.
This turns off certain features of GCC that are incompatible with
ISO C90 (when compiling C code), or of standard C++ (when compiling
C++ code), such as the asm and typeof keywords, and predefined
macros such as 'unix' and 'vax' that identify the type of system
you are using. It also enables the undesirable and rarely used ISO
trigraph feature. For the C compiler, it disables recognition of
C++ style // comments as well as the inline keyword.
(It uses vax in the example instead of linux because when it was written maybe it was more popular ;-).
The basic idea is that GCC only tries to fully comply with the ISO standards when it is invoked with the -ansi option.
Use this command
gcc -dM -E - < /dev/null
to get this
#define _LP64 1
#define _STDC_PREDEF_H 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_HLE_ACQUIRE 65536
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BIGGEST_ALIGNMENT__ 16
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ short unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __DBL_DECIMAL_DIG__ 17
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L)
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-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)1.79769313486231570815e+308L)
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ ((double)2.22507385850720138309e-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_BID_FORMAT__ 1
#define __DECIMAL_DIG__ 21
#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__ 1.40129846432481707092e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209289550781250000e-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__ 3.40282346638528859812e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435082228750797e-38F
#define __FLT_RADIX__ 2
#define __FXSR__ 1
#define __GCC_ASM_FLAG_OUTPUTS__ 1
#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 __GCC_HAVE_DWARF2_CFI_ASM 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_IEC_559 2
#define __GCC_IEC_559_COMPLEX 2
#define __GNUC_MINOR__ 3
#define __GNUC_PATCHLEVEL__ 0
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 6
#define __GXX_ABI_VERSION 1010
#define __INT16_C(c) c
#define __INT16_MAX__ 0x7fff
#define __INT16_TYPE__ short int
#define __INT32_C(c) c
#define __INT32_MAX__ 0x7fffffff
#define __INT32_TYPE__ int
#define __INT64_C(c) c ## L
#define __INT64_MAX__ 0x7fffffffffffffffL
#define __INT64_TYPE__ long int
#define __INT8_C(c) c
#define __INT8_MAX__ 0x7f
#define __INT8_TYPE__ signed char
#define __INTMAX_C(c) c ## L
#define __INTMAX_MAX__ 0x7fffffffffffffffL
#define __INTMAX_TYPE__ long int
#define __INTPTR_MAX__ 0x7fffffffffffffffL
#define __INTPTR_TYPE__ long int
#define __INT_FAST16_MAX__ 0x7fffffffffffffffL
#define __INT_FAST16_TYPE__ long int
#define __INT_FAST32_MAX__ 0x7fffffffffffffffL
#define __INT_FAST32_TYPE__ long int
#define __INT_FAST64_MAX__ 0x7fffffffffffffffL
#define __INT_FAST64_TYPE__ long int
#define __INT_FAST8_MAX__ 0x7f
#define __INT_FAST8_TYPE__ signed char
#define __INT_LEAST16_MAX__ 0x7fff
#define __INT_LEAST16_TYPE__ short int
#define __INT_LEAST32_MAX__ 0x7fffffff
#define __INT_LEAST32_TYPE__ int
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffL
#define __INT_LEAST64_TYPE__ long int
#define __INT_LEAST8_MAX__ 0x7f
#define __INT_LEAST8_TYPE__ signed char
#define __INT_MAX__ 0x7fffffff
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __LDBL_DIG__ 18
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 64
#define __LDBL_MAX_10_EXP__ 4932
#define __LDBL_MAX_EXP__ 16384
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __LDBL_MIN_10_EXP__ (-4931)
#define __LDBL_MIN_EXP__ (-16381)
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __LONG_LONG_MAX__ 0x7fffffffffffffffLL
#define __LONG_MAX__ 0x7fffffffffffffffL
#define __LP64__ 1
#define __MMX__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __PIE__ 2
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_MAX__ 0x7fffffffffffffffL
#define __PTRDIFF_TYPE__ long int
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 0x7f
#define __SEG_FS 1
#define __SEG_GS 1
#define __SHRT_MAX__ 0x7fff
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __SIG_ATOMIC_TYPE__ int
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT128__ 16
#define __SIZEOF_FLOAT80__ 16
#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__ 0xffffffffffffffffUL
#define __SIZE_TYPE__ long unsigned int
#define __SSE2_MATH__ 1
#define __SSE2__ 1
#define __SSE_MATH__ 1
#define __SSE__ 1
#define __SSP_STRONG__ 3
#define __STDC_HOSTED__ 1
#define __STDC_IEC_559_COMPLEX__ 1
#define __STDC_IEC_559__ 1
#define __STDC_ISO_10646__ 201605L
#define __STDC_NO_THREADS__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 201112L
#define __STDC__ 1
#define __UINT16_C(c) c
#define __UINT16_MAX__ 0xffff
#define __UINT16_TYPE__ short unsigned int
#define __UINT32_C(c) c ## U
#define __UINT32_MAX__ 0xffffffffU
#define __UINT32_TYPE__ unsigned int
#define __UINT64_C(c) c ## UL
#define __UINT64_MAX__ 0xffffffffffffffffUL
#define __UINT64_TYPE__ long unsigned int
#define __UINT8_C(c) c
#define __UINT8_MAX__ 0xff
#define __UINT8_TYPE__ unsigned char
#define __UINTMAX_C(c) c ## UL
#define __UINTMAX_MAX__ 0xffffffffffffffffUL
#define __UINTMAX_TYPE__ long unsigned int
#define __UINTPTR_MAX__ 0xffffffffffffffffUL
#define __UINTPTR_TYPE__ long unsigned int
#define __UINT_FAST16_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST16_TYPE__ long unsigned int
#define __UINT_FAST32_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST32_TYPE__ long unsigned int
#define __UINT_FAST64_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST64_TYPE__ long unsigned int
#define __UINT_FAST8_MAX__ 0xff
#define __UINT_FAST8_TYPE__ unsigned char
#define __UINT_LEAST16_MAX__ 0xffff
#define __UINT_LEAST16_TYPE__ short unsigned int
#define __UINT_LEAST32_MAX__ 0xffffffffU
#define __UINT_LEAST32_TYPE__ unsigned int
#define __UINT_LEAST64_MAX__ 0xffffffffffffffffUL
#define __UINT_LEAST64_TYPE__ long unsigned int
#define __UINT_LEAST8_MAX__ 0xff
#define __UINT_LEAST8_TYPE__ unsigned char
#define __USER_LABEL_PREFIX__
#define __VERSION__ "6.3.0 20170406"
#define __WCHAR_MAX__ 0x7fffffff
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
#define __WCHAR_TYPE__ int
#define __WINT_MAX__ 0xffffffffU
#define __WINT_MIN__ 0U
#define __WINT_TYPE__ unsigned int
#define __amd64 1
#define __amd64__ 1
#define __code_model_small__ 1
#define __gnu_linux__ 1
#define __has_include(STR) __has_include__(STR)
#define __has_include_next(STR) __has_include_next__(STR)
#define __k8 1
#define __k8__ 1
#define __linux 1
#define __linux__ 1
#define __pic__ 2
#define __pie__ 2
#define __unix 1
#define __unix__ 1
#define __x86_64 1
#define __x86_64__ 1
#define linux 1
#define unix 1
X32 is an ABI for amd64/x86_64 CPUs using 32-bit pointers. The idea is to combine the larger register set of x86_64 with the smaller memory and cache footprint resulting from 32-bit pointers. It provides up to about a 40% speedup. See Difference between x86, x32, and x64 architectures on Stack Overflow, and the Debian X32 Ports wiki page for details and setting it up as a chroot environment.
We have a bug report from a Debian maintainer under the environment. The report is adcq is an illegal instruction. The inline assembly is activated based on preprocessor macros, so we are not detecting X32 properly (or more correctly, not at all until now).
The most obvious choice (to me) for a preprocessor macro is something like __X32__, but that's not offered. Based on Clang's patch and Debian's suggestion, it looks like __ILP32__ can be used. But I'd like a more canonical answer since _ILP32 and __code_model_small__ look interesting, too. (And I'm aware of issues with SSE2, where the compiler supported it but the OS did not).
What are the preprocessor macros that can be used to reliably detect an X32 ABI and environment when using Clang and GCC?
To be clear, I'm not trying to fix the code at this point. I just want to know the macros that can be used in a complete remediation.
# cpp -dM < /dev/null | sort
#define __amd64 1
#define __amd64__ 1
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_CONSUME 1
#define __ATOMIC_HLE_ACQUIRE 65536
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BIGGEST_ALIGNMENT__ 16
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ short unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __code_model_small__ 1
#define __DBL_DECIMAL_DIG__ 17
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L)
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-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__ ((double)1.79769313486231570815e+308L)
#define __DBL_MAX_EXP__ 1024
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN__ ((double)2.22507385850720138309e-308L)
#define __DBL_MIN_EXP__ (-1021)
#define __DEC128_EPSILON__ 1E-33DL
#define __DEC128_MANT_DIG__ 34
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL
#define __DEC128_MAX_EXP__ 6145
#define __DEC128_MIN__ 1E-6143DL
#define __DEC128_MIN_EXP__ (-6142)
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL
#define __DEC32_EPSILON__ 1E-6DF
#define __DEC32_MANT_DIG__ 7
#define __DEC32_MAX__ 9.999999E96DF
#define __DEC32_MAX_EXP__ 97
#define __DEC32_MIN__ 1E-95DF
#define __DEC32_MIN_EXP__ (-94)
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF
#define __DEC64_EPSILON__ 1E-15DD
#define __DEC64_MANT_DIG__ 16
#define __DEC64_MAX__ 9.999999999999999E384DD
#define __DEC64_MAX_EXP__ 385
#define __DEC64_MIN__ 1E-383DD
#define __DEC64_MIN_EXP__ (-382)
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD
#define __DEC_EVAL_METHOD__ 2
#define __DECIMAL_BID_FORMAT__ 1
#define __DECIMAL_DIG__ 21
#define __ELF__ 1
#define __FINITE_MATH_ONLY__ 0
#define __FLOAT_WORD_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __FLT_DECIMAL_DIG__ 9
#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209289550781250000e-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__ 3.40282346638528859812e+38F
#define __FLT_MAX_EXP__ 128
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN__ 1.17549435082228750797e-38F
#define __FLT_MIN_EXP__ (-125)
#define __FLT_RADIX__ 2
#define __FXSR__ 1
#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 __GCC_HAVE_DWARF2_CFI_ASM 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_IEC_559 2
#define __GCC_IEC_559_COMPLEX 2
#define __GNUC__ 5
#define __GNUC_MINOR__ 2
#define __GNUC_PATCHLEVEL__ 1
#define __GNUC_STDC_INLINE__ 1
#define __gnu_linux__ 1
#define __GXX_ABI_VERSION 1009
#define __has_include_next(STR) __has_include_next__(STR)
#define __has_include(STR) __has_include__(STR)
#define __ILP32__ 1
#define _ILP32 1
#define __INT16_C(c) c
#define __INT16_MAX__ 0x7fff
#define __INT16_TYPE__ short int
#define __INT32_C(c) c
#define __INT32_MAX__ 0x7fffffff
#define __INT32_TYPE__ int
#define __INT64_C(c) c ## LL
#define __INT64_MAX__ 0x7fffffffffffffffLL
#define __INT64_TYPE__ long long int
#define __INT8_C(c) c
#define __INT8_MAX__ 0x7f
#define __INT8_TYPE__ signed char
#define __INT_FAST16_MAX__ 0x7fffffff
#define __INT_FAST16_TYPE__ int
#define __INT_FAST32_MAX__ 0x7fffffff
#define __INT_FAST32_TYPE__ int
#define __INT_FAST64_MAX__ 0x7fffffffffffffffLL
#define __INT_FAST64_TYPE__ long long int
#define __INT_FAST8_MAX__ 0x7f
#define __INT_FAST8_TYPE__ signed char
#define __INT_LEAST16_MAX__ 0x7fff
#define __INT_LEAST16_TYPE__ short int
#define __INT_LEAST32_MAX__ 0x7fffffff
#define __INT_LEAST32_TYPE__ int
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffLL
#define __INT_LEAST64_TYPE__ long long int
#define __INT_LEAST8_MAX__ 0x7f
#define __INT_LEAST8_TYPE__ signed char
#define __INT_MAX__ 0x7fffffff
#define __INTMAX_C(c) c ## LL
#define __INTMAX_MAX__ 0x7fffffffffffffffLL
#define __INTMAX_TYPE__ long long int
#define __INTPTR_MAX__ 0x7fffffff
#define __INTPTR_TYPE__ int
#define __k8 1
#define __k8__ 1
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __LDBL_DIG__ 18
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 64
#define __LDBL_MAX_10_EXP__ 4932
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __LDBL_MAX_EXP__ 16384
#define __LDBL_MIN_10_EXP__ (-4931)
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __LDBL_MIN_EXP__ (-16381)
#define __linux 1
#define __linux__ 1
#define linux 1
#define __LONG_LONG_MAX__ 0x7fffffffffffffffLL
#define __LONG_MAX__ 0x7fffffffL
#define __MMX__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_MAX__ 0x7fffffff
#define __PTRDIFF_TYPE__ int
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 0x7f
#define __SHRT_MAX__ 0x7fff
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __SIG_ATOMIC_TYPE__ int
#define __SIZE_MAX__ 0xffffffffU
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT128__ 16
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_FLOAT80__ 16
#define __SIZEOF_INT128__ 16
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG__ 4
#define __SIZEOF_LONG_DOUBLE__ 16
#define __SIZEOF_LONG_LONG__ 8
#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_TYPE__ unsigned int
#define __SSE__ 1
#define __SSE2__ 1
#define __SSE2_MATH__ 1
#define __SSE_MATH__ 1
#define __STDC__ 1
#define __STDC_HOSTED__ 1
#define __STDC_IEC_559__ 1
#define __STDC_IEC_559_COMPLEX__ 1
#define __STDC_ISO_10646__ 201103L
#define __STDC_NO_THREADS__ 1
#define _STDC_PREDEF_H 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 201112L
#define __UINT16_C(c) c
#define __UINT16_MAX__ 0xffff
#define __UINT16_TYPE__ short unsigned int
#define __UINT32_C(c) c ## U
#define __UINT32_MAX__ 0xffffffffU
#define __UINT32_TYPE__ unsigned int
#define __UINT64_C(c) c ## ULL
#define __UINT64_MAX__ 0xffffffffffffffffULL
#define __UINT64_TYPE__ long long unsigned int
#define __UINT8_C(c) c
#define __UINT8_MAX__ 0xff
#define __UINT8_TYPE__ unsigned char
#define __UINT_FAST16_MAX__ 0xffffffffU
#define __UINT_FAST16_TYPE__ unsigned int
#define __UINT_FAST32_MAX__ 0xffffffffU
#define __UINT_FAST32_TYPE__ unsigned int
#define __UINT_FAST64_MAX__ 0xffffffffffffffffULL
#define __UINT_FAST64_TYPE__ long long unsigned int
#define __UINT_FAST8_MAX__ 0xff
#define __UINT_FAST8_TYPE__ unsigned char
#define __UINT_LEAST16_MAX__ 0xffff
#define __UINT_LEAST16_TYPE__ short unsigned int
#define __UINT_LEAST32_MAX__ 0xffffffffU
#define __UINT_LEAST32_TYPE__ unsigned int
#define __UINT_LEAST64_MAX__ 0xffffffffffffffffULL
#define __UINT_LEAST64_TYPE__ long long unsigned int
#define __UINT_LEAST8_MAX__ 0xff
#define __UINT_LEAST8_TYPE__ unsigned char
#define __UINTMAX_C(c) c ## ULL
#define __UINTMAX_MAX__ 0xffffffffffffffffULL
#define __UINTMAX_TYPE__ long long unsigned int
#define __UINTPTR_MAX__ 0xffffffffU
#define __UINTPTR_TYPE__ unsigned int
#define __unix 1
#define __unix__ 1
#define unix 1
#define __USER_LABEL_PREFIX__
#define __VERSION__ "5.2.1 20150911"
#define __WCHAR_MAX__ 0x7fffffffL
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
#define __WCHAR_TYPE__ long int
#define __WINT_MAX__ 0xffffffffU
#define __WINT_MIN__ 0U
#define __WINT_TYPE__ unsigned int
#define __x86_64 1
#define __x86_64__ 1
There doesn't appear to be a predefined macro that explicitly specifies an x32 environment. Comparing the output of cpp -dM and cpp -dM -mx32, the symbols _ILP32 and __ILP32__ are defined only for x32, and _LP64 and __LP64__ are defined only for x86_64 without x32. A number of other predefined macros have different values for the two environments.
I think the most straightforward way to detect x32 at compile time is to examine the __x86_64__ and SIZE_MAX macros. The former is predefined (or not) by gcc, and the latter is defined in <stdint.h>.
The following program demonstrates this. It works correctly with gcc -m64, gcc -m32, and gcc -mx32 on an x86_64 system,, and with gcc on a non-x86_64 system (SPARC).
#include <stdio.h>
#include <stdint.h>
int main(void) {
#ifdef __x86_64__
#if SIZE_MAX == 0xFFFFFFFF
puts("This is x32");
#else
puts("This is x86_64 but not x32");
#endif
#else
puts("This is not x64_64");
#endif
}
Seems The Debian pages have been updated.
From https://wiki.debian.org/X32Port
When X32 is being targeted, both X32 and x86_64 preprocessor macros are defined. To detect X32, you should use both __ILP32__ and __x86_64__ rather than __amd64__, __x86_64__ or __LP64__.
I understand the basics to the #if #endif preprocessor directives in C, in that depending which expression evaluates to be true, the proceeding code within the #if will be compiled, however I'm currently learning portaudio(I'm making a VOIP app for school) and I'm looking over some of their examples and I've become confused over a small section
/* Select sample format. */
#if 1
#define PA_SAMPLE_TYPE paFloat32
typedef float SAMPLE;
#define SAMPLE_SILENCE (0.0f)
#define PRINTF_S_FORMAT "%.8f"
#elif 1
#define PA_SAMPLE_TYPE paInt16
typedef short SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
#elif 0
#define PA_SAMPLE_TYPE paInt8
typedef char SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
#else
#define PA_SAMPLE_TYPE paUInt8
typedef unsigned char SAMPLE;
#define SAMPLE_SILENCE (128)
#define PRINTF_S_FORMAT "%d"
#endif
the first question that comes to mind is
#if 1
#define PA_SAMPLE_TYPE paFloat32
typedef float SAMPLE;
#define SAMPLE_SILENCE (0.0f)
#define PRINTF_S_FORMAT "%.8f"
#elif 1
#define PA_SAMPLE_TYPE paInt16
typedef short SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
wont the #elif 1 always be skipped because if somehow #if 1 (#if true) evaluates to false, wont #elif 1 also evaluate to false?
question 2
isn't 1 evaluate to true and 0 to false? so wont #elif 0 always evaluate to false? i.e it doesn't really matter?
question 3
I'm going to be sending these samples over a socket, is skipping this preprocessor directive and just working with the code
#define PA_SAMPLE_TYPE paInt8
typedef char SAMPLE;
#define SAMPLE_SILENCE (0)
#define PRINTF_S_FORMAT "%d"
or
#define PA_SAMPLE_TYPE paUInt8
typedef unsigned char SAMPLE;
#define SAMPLE_SILENCE (128)
#define PRINTF_S_FORMAT "%d"
#endif
Would that be beter so as my SAMPLE_TYPE/SAMPLE can be treated as an array of characters/ Unsigned Characters (not having to convert floats to chars and then back again) for writing/reading from the socket?
What you need to understand is between a sequence of #if / #elif / #else, only one condition will be selected:
#if is selected here:
#if 1
// only this one will be selected
#elif 1
#else
#endif
#elif is selected here:
#if 0
#elif 1
// only this one will be selected
#else
#endif
#else is selected here:
#if 0
#elif 0
#else
// only this one will be selected
#endif
Why does the C preprocessor in GCC interpret the word linux (small letters) as the constant 1?
test.c:
#include <stdio.h>
int main(void)
{
int linux = 5;
return 0;
}
Result of $ gcc -E test.c (stop after the preprocessing stage):
....
int main(void)
{
int 1 = 5;
return 0;
}
Which of course yields an error.
(BTW: There is no #define linux in the stdio.h file.)
In the Old Days (pre-ANSI), predefining symbols such as unix and vax was a way to allow code to detect at compile time what system it was being compiled for. There was no official language standard back then (beyond the reference material at the back of the first edition of K&R), and C code of any complexity was typically a complex maze of #ifdefs to allow for differences between systems. These macro definitions were generally set by the compiler itself, not defined in a library header file. Since there were no real rules about which identifiers could be used by the implementation and which were reserved for programmers, compiler writers felt free to use simple names like unix and assumed that programmers would simply avoid using those names for their own purposes.
The 1989 ANSI C standard introduced rules restricting what symbols an implementation could legally predefine. A macro predefined by the compiler could only have a name starting with two underscores, or with an underscore followed by an uppercase letter, leaving programmers free to use identifiers not matching that pattern and not used in the standard library.
As a result, any compiler that predefines unix or linux is non-conforming, since it will fail to compile perfectly legal code that uses something like int linux = 5;.
As it happens, gcc is non-conforming by default -- but it can be made to conform (reasonably well) with the right command-line options:
gcc -std=c90 -pedantic ... # or -std=c89 or -ansi
gcc -std=c99 -pedantic
gcc -std=c11 -pedantic
See the gcc manual for more details.
gcc will be phasing out these definitions in future releases, so you shouldn't write code that depends on them. If your program needs to know whether it's being compiled for a Linux target or not it can check whether __linux__ is defined (assuming you're using gcc or a compiler that's compatible with it). See the GNU C preprocessor manual for more information.
A largely irrelevant aside: the "Best One Liner" winner of the 1987 International Obfuscated C Code Contest, by David Korn (yes, the author of the Korn Shell) took advantage of the predefined unix macro:
main() { printf(&unix["\021%six\012\0"],(unix)["have"]+"fun"-0x60);}
It prints "unix", but for reasons that have absolutely nothing to do with the spelling of the macro name.
I don't want to post any spoilers here, and I encourage anyone reading this to try to understand that code on their own first. But if you really want to give up, I've posted an explanation here:
https://gist.github.com/Keith-S-Thompson/6920347
This appears to be an (undocumented) "GNU extension": [correction: I finally found a mention in the docs. See below.]
The following command uses the -dM option to print all preprocessor defines; since the input "file" is empty, it shows exactly the predefined macros. It was run with gcc-4.7.3 on a standard ubuntu install. You can see that the preprocessor is standard-aware. In total, there 243 macros with -std=gnu99 and 240 with -std=c99; I filtered the output for relevance.
$ cpp --std=c89 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
$ cpp --std=gnu89 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
#define linux 1
$ cpp --std=c99 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
$ cpp --std=gnu99 -dM < /dev/null | grep linux
#define __linux 1
#define __linux__ 1
#define __gnu_linux__ 1
#define linux 1
The "gnu standard" versions also #define unix. (Using c11 and gnu11 produces the same results.)
I suppose they had their reasons, but it seems to me to make the default installation of gcc (which compiles C code with -std=gnu89 unless otherwise specified) non-conformant, and -- as in this question -- surprising. Polluting the global namespace with macros whose names don't begin with an underscore is not permitted in a conformant implementation. (6.8.10p2: "Any other predefined macro names shall begin with a leading underscore followed by an uppercase letter or a second
underscore," but, as mentioned in Appendix J.5 (portability issues), such names are often predefined.)
When I originally wrote this answer, I wasn't able to find any documentation in gcc about this issue, but I did finally discover it, not in C implementation-defined behaviour nor in C extensions but in the cpp manual section 3.7.3, where it notes that:
We are slowly phasing out all predefined macros which are outside the reserved namespace. You should never use them in new programs…
Because linux is a built-in macro defined when the compiler is running on, or compiling for (if it is a cross-compiler), Linux.
There are a lot of such predefined macros. With GCC, you can use:
cp /dev/null emptyfile.c
gcc -E -dM emptyfile.c
to get a list of macros. (I've not managed to persuade GCC to accept /dev/null directly, but
the empty file seems to work OK.) With GCC 4.8.1 running on Mac OS X 10.8.5, I got the output:
#define __DBL_MIN_EXP__ (-1021)
#define __UINT_LEAST16_MAX__ 65535
#define __ATOMIC_ACQUIRE 2
#define __FLT_MIN__ 1.17549435082228750797e-38F
#define __UINT_LEAST8_TYPE__ unsigned char
#define __INTMAX_C(c) c ## L
#define __CHAR_BIT__ 8
#define __UINT8_MAX__ 255
#define __WINT_MAX__ 2147483647
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __SIZE_MAX__ 18446744073709551615UL
#define __WCHAR_MAX__ 2147483647
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L)
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_ATOMIC_CHAR_LOCK_FREE 2
#define __FLT_EVAL_METHOD__ 0
#define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
#define __x86_64 1
#define __UINT_FAST64_MAX__ 18446744073709551615ULL
#define __SIG_ATOMIC_TYPE__ int
#define __DBL_MIN_10_EXP__ (-307)
#define __FINITE_MATH_ONLY__ 0
#define __GNUC_PATCHLEVEL__ 1
#define __UINT_FAST8_MAX__ 255
#define __DEC64_MAX_EXP__ 385
#define __INT8_C(c) c
#define __UINT_LEAST64_MAX__ 18446744073709551615ULL
#define __SHRT_MAX__ 32767
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __UINT_LEAST8_MAX__ 255
#define __GCC_ATOMIC_BOOL_LOCK_FREE 2
#define __APPLE_CC__ 1
#define __UINTMAX_TYPE__ long unsigned int
#define __DEC32_EPSILON__ 1E-6DF
#define __UINT32_MAX__ 4294967295U
#define __LDBL_MAX_EXP__ 16384
#define __WINT_MIN__ (-__WINT_MAX__ - 1)
#define __SCHAR_MAX__ 127
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
#define __INT64_C(c) c ## LL
#define __DBL_DIG__ 15
#define __GCC_ATOMIC_POINTER_LOCK_FREE 2
#define __SIZEOF_INT__ 4
#define __SIZEOF_POINTER__ 8
#define __USER_LABEL_PREFIX__ _
#define __STDC_HOSTED__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __FLT_EPSILON__ 1.19209289550781250000e-7F
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __DEC32_MAX__ 9.999999E96DF
#define __strong
#define __INT32_MAX__ 2147483647
#define __SIZEOF_LONG__ 8
#define __APPLE__ 1
#define __UINT16_C(c) c
#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 __SIZEOF_LONG_DOUBLE__ 16
#define __BIGGEST_ALIGNMENT__ 16
#define __DBL_MAX__ ((double)1.79769313486231570815e+308L)
#define __INT_FAST32_MAX__ 2147483647
#define __DBL_HAS_INFINITY__ 1
#define __DEC32_MIN_EXP__ (-94)
#define __INT_FAST16_TYPE__ short int
#define __LDBL_HAS_DENORM__ 1
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL
#define __INT_LEAST32_MAX__ 2147483647
#define __DEC32_MIN__ 1E-95DF
#define __weak
#define __DBL_MAX_EXP__ 1024
#define __DEC128_EPSILON__ 1E-33DL
#define __SSE2_MATH__ 1
#define __ATOMIC_HLE_RELEASE 131072
#define __PTRDIFF_MAX__ 9223372036854775807L
#define __amd64 1
#define __tune_core2__ 1
#define __ATOMIC_HLE_ACQUIRE 65536
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __SIZEOF_SIZE_T__ 8
#define __SIZEOF_WINT_T__ 4
#define __GXX_ABI_VERSION 1002
#define __FLT_MIN_EXP__ (-125)
#define __INT_FAST64_TYPE__ long long int
#define __DBL_MIN__ ((double)2.22507385850720138309e-308L)
#define __LP64__ 1
#define __DEC128_MIN__ 1E-6143DL
#define __REGISTER_PREFIX__
#define __UINT16_MAX__ 65535
#define __DBL_HAS_DENORM__ 1
#define __UINT8_TYPE__ unsigned char
#define __NO_INLINE__ 1
#define __FLT_MANT_DIG__ 24
#define __VERSION__ "4.8.1"
#define __UINT64_C(c) c ## ULL
#define __GCC_ATOMIC_INT_LOCK_FREE 2
#define __FLOAT_WORD_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __INT32_C(c) c
#define __DEC64_EPSILON__ 1E-15DD
#define __ORDER_PDP_ENDIAN__ 3412
#define __DEC128_MIN_EXP__ (-6142)
#define __INT_FAST32_TYPE__ int
#define __UINT_LEAST16_TYPE__ short unsigned int
#define __INT16_MAX__ 32767
#define __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ 1080
#define __SIZE_TYPE__ long unsigned int
#define __UINT64_MAX__ 18446744073709551615ULL
#define __INT8_TYPE__ signed char
#define __FLT_RADIX__ 2
#define __INT_LEAST16_TYPE__ short int
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __UINTMAX_C(c) c ## UL
#define __SSE_MATH__ 1
#define __k8 1
#define __SIG_ATOMIC_MAX__ 2147483647
#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
#define __SIZEOF_PTRDIFF_T__ 8
#define __x86_64__ 1
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF
#define __INT_FAST16_MAX__ 32767
#define __UINT_FAST32_MAX__ 4294967295U
#define __UINT_LEAST64_TYPE__ long long unsigned int
#define __FLT_HAS_QUIET_NAN__ 1
#define __FLT_MAX_10_EXP__ 38
#define __LONG_MAX__ 9223372036854775807L
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL
#define __FLT_HAS_INFINITY__ 1
#define __UINT_FAST16_TYPE__ short unsigned int
#define __DEC64_MAX__ 9.999999999999999E384DD
#define __CHAR16_TYPE__ short unsigned int
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __INT_LEAST16_MAX__ 32767
#define __DEC64_MANT_DIG__ 16
#define __INT64_MAX__ 9223372036854775807LL
#define __UINT_LEAST32_MAX__ 4294967295U
#define __GCC_ATOMIC_LONG_LOCK_FREE 2
#define __INT_LEAST64_TYPE__ long long int
#define __INT16_TYPE__ short int
#define __INT_LEAST8_TYPE__ signed char
#define __DEC32_MAX_EXP__ 97
#define __INT_FAST8_MAX__ 127
#define __INTPTR_MAX__ 9223372036854775807L
#define __LITTLE_ENDIAN__ 1
#define __SSE2__ 1
#define __LDBL_MANT_DIG__ 64
#define __CONSTANT_CFSTRINGS__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __code_model_small__ 1
#define __k8__ 1
#define __INTPTR_TYPE__ long int
#define __UINT16_TYPE__ short unsigned int
#define __WCHAR_TYPE__ int
#define __SIZEOF_FLOAT__ 4
#define __pic__ 2
#define __UINTPTR_MAX__ 18446744073709551615UL
#define __DEC64_MIN_EXP__ (-382)
#define __INT_FAST64_MAX__ 9223372036854775807LL
#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
#define __FLT_DIG__ 6
#define __UINT_FAST64_TYPE__ long long unsigned int
#define __INT_MAX__ 2147483647
#define __MACH__ 1
#define __amd64__ 1
#define __INT64_TYPE__ long long int
#define __FLT_MAX_EXP__ 128
#define __ORDER_BIG_ENDIAN__ 4321
#define __DBL_MANT_DIG__ 53
#define __INT_LEAST64_MAX__ 9223372036854775807LL
#define __GCC_ATOMIC_CHAR16_T_LOCK_FREE 2
#define __DEC64_MIN__ 1E-383DD
#define __WINT_TYPE__ int
#define __UINT_LEAST32_TYPE__ unsigned int
#define __SIZEOF_SHORT__ 2
#define __SSE__ 1
#define __LDBL_MIN_EXP__ (-16381)
#define __INT_LEAST8_MAX__ 127
#define __SIZEOF_INT128__ 16
#define __LDBL_MAX_10_EXP__ 4932
#define __ATOMIC_RELAXED 0
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-16L)
#define _LP64 1
#define __UINT8_C(c) c
#define __INT_LEAST32_TYPE__ int
#define __SIZEOF_WCHAR_T__ 4
#define __UINT64_TYPE__ long long unsigned int
#define __INT_FAST8_TYPE__ signed char
#define __DBL_DECIMAL_DIG__ 17
#define __FXSR__ 1
#define __DEC_EVAL_METHOD__ 2
#define __UINT32_C(c) c ## U
#define __INTMAX_MAX__ 9223372036854775807L
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
#define __INT8_MAX__ 127
#define __PIC__ 2
#define __UINT_FAST32_TYPE__ unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __FLT_MAX__ 3.40282346638528859812e+38F
#define __INT32_TYPE__ int
#define __SIZEOF_DOUBLE__ 8
#define __FLT_MIN_10_EXP__ (-37)
#define __INTMAX_TYPE__ long int
#define __DEC128_MAX_EXP__ 6145
#define __ATOMIC_CONSUME 1
#define __GNUC_MINOR__ 8
#define __UINTMAX_MAX__ 18446744073709551615UL
#define __DEC32_MANT_DIG__ 7
#define __DBL_MAX_10_EXP__ 308
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __INT16_C(c) c
#define __STDC__ 1
#define __PTRDIFF_TYPE__ long int
#define __ATOMIC_SEQ_CST 5
#define __UINT32_TYPE__ unsigned int
#define __UINTPTR_TYPE__ long unsigned int
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD
#define __DEC128_MANT_DIG__ 34
#define __LDBL_MIN_10_EXP__ (-4931)
#define __SIZEOF_LONG_LONG__ 8
#define __GCC_ATOMIC_LLONG_LOCK_FREE 2
#define __LDBL_DIG__ 18
#define __FLT_DECIMAL_DIG__ 9
#define __UINT_FAST16_MAX__ 65535
#define __GNUC_GNU_INLINE__ 1
#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
#define __SSE3__ 1
#define __UINT_FAST8_TYPE__ unsigned char
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_RELEASE 3
That's 236 macros from an empty file. When I added #include <stdio.h> to the file, the number of macros defined went up to 505. These includes all sorts of platform-identifying macros.
From info gcc (emphasis mine):
-ansi
In C mode, this is equivalent to -std=c90. In C++ mode, it is
equivalent to -std=c++98.
This turns off certain features of GCC that are incompatible with
ISO C90 (when compiling C code), or of standard C++ (when compiling
C++ code), such as the asm and typeof keywords, and predefined
macros such as 'unix' and 'vax' that identify the type of system
you are using. It also enables the undesirable and rarely used ISO
trigraph feature. For the C compiler, it disables recognition of
C++ style // comments as well as the inline keyword.
(It uses vax in the example instead of linux because when it was written maybe it was more popular ;-).
The basic idea is that GCC only tries to fully comply with the ISO standards when it is invoked with the -ansi option.
Use this command
gcc -dM -E - < /dev/null
to get this
#define _LP64 1
#define _STDC_PREDEF_H 1
#define __ATOMIC_ACQUIRE 2
#define __ATOMIC_ACQ_REL 4
#define __ATOMIC_CONSUME 1
#define __ATOMIC_HLE_ACQUIRE 65536
#define __ATOMIC_HLE_RELEASE 131072
#define __ATOMIC_RELAXED 0
#define __ATOMIC_RELEASE 3
#define __ATOMIC_SEQ_CST 5
#define __BIGGEST_ALIGNMENT__ 16
#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
#define __CHAR16_TYPE__ short unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __CHAR_BIT__ 8
#define __DBL_DECIMAL_DIG__ 17
#define __DBL_DENORM_MIN__ ((double)4.94065645841246544177e-324L)
#define __DBL_DIG__ 15
#define __DBL_EPSILON__ ((double)2.22044604925031308085e-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)1.79769313486231570815e+308L)
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN__ ((double)2.22507385850720138309e-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_BID_FORMAT__ 1
#define __DECIMAL_DIG__ 21
#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__ 1.40129846432481707092e-45F
#define __FLT_DIG__ 6
#define __FLT_EPSILON__ 1.19209289550781250000e-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__ 3.40282346638528859812e+38F
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN__ 1.17549435082228750797e-38F
#define __FLT_RADIX__ 2
#define __FXSR__ 1
#define __GCC_ASM_FLAG_OUTPUTS__ 1
#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 __GCC_HAVE_DWARF2_CFI_ASM 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
#define __GCC_IEC_559 2
#define __GCC_IEC_559_COMPLEX 2
#define __GNUC_MINOR__ 3
#define __GNUC_PATCHLEVEL__ 0
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 6
#define __GXX_ABI_VERSION 1010
#define __INT16_C(c) c
#define __INT16_MAX__ 0x7fff
#define __INT16_TYPE__ short int
#define __INT32_C(c) c
#define __INT32_MAX__ 0x7fffffff
#define __INT32_TYPE__ int
#define __INT64_C(c) c ## L
#define __INT64_MAX__ 0x7fffffffffffffffL
#define __INT64_TYPE__ long int
#define __INT8_C(c) c
#define __INT8_MAX__ 0x7f
#define __INT8_TYPE__ signed char
#define __INTMAX_C(c) c ## L
#define __INTMAX_MAX__ 0x7fffffffffffffffL
#define __INTMAX_TYPE__ long int
#define __INTPTR_MAX__ 0x7fffffffffffffffL
#define __INTPTR_TYPE__ long int
#define __INT_FAST16_MAX__ 0x7fffffffffffffffL
#define __INT_FAST16_TYPE__ long int
#define __INT_FAST32_MAX__ 0x7fffffffffffffffL
#define __INT_FAST32_TYPE__ long int
#define __INT_FAST64_MAX__ 0x7fffffffffffffffL
#define __INT_FAST64_TYPE__ long int
#define __INT_FAST8_MAX__ 0x7f
#define __INT_FAST8_TYPE__ signed char
#define __INT_LEAST16_MAX__ 0x7fff
#define __INT_LEAST16_TYPE__ short int
#define __INT_LEAST32_MAX__ 0x7fffffff
#define __INT_LEAST32_TYPE__ int
#define __INT_LEAST64_MAX__ 0x7fffffffffffffffL
#define __INT_LEAST64_TYPE__ long int
#define __INT_LEAST8_MAX__ 0x7f
#define __INT_LEAST8_TYPE__ signed char
#define __INT_MAX__ 0x7fffffff
#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
#define __LDBL_DIG__ 18
#define __LDBL_EPSILON__ 1.08420217248550443401e-19L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 64
#define __LDBL_MAX_10_EXP__ 4932
#define __LDBL_MAX_EXP__ 16384
#define __LDBL_MAX__ 1.18973149535723176502e+4932L
#define __LDBL_MIN_10_EXP__ (-4931)
#define __LDBL_MIN_EXP__ (-16381)
#define __LDBL_MIN__ 3.36210314311209350626e-4932L
#define __LONG_LONG_MAX__ 0x7fffffffffffffffLL
#define __LONG_MAX__ 0x7fffffffffffffffL
#define __LP64__ 1
#define __MMX__ 1
#define __NO_INLINE__ 1
#define __ORDER_BIG_ENDIAN__ 4321
#define __ORDER_LITTLE_ENDIAN__ 1234
#define __ORDER_PDP_ENDIAN__ 3412
#define __PIC__ 2
#define __PIE__ 2
#define __PRAGMA_REDEFINE_EXTNAME 1
#define __PTRDIFF_MAX__ 0x7fffffffffffffffL
#define __PTRDIFF_TYPE__ long int
#define __REGISTER_PREFIX__
#define __SCHAR_MAX__ 0x7f
#define __SEG_FS 1
#define __SEG_GS 1
#define __SHRT_MAX__ 0x7fff
#define __SIG_ATOMIC_MAX__ 0x7fffffff
#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
#define __SIG_ATOMIC_TYPE__ int
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_FLOAT128__ 16
#define __SIZEOF_FLOAT80__ 16
#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__ 0xffffffffffffffffUL
#define __SIZE_TYPE__ long unsigned int
#define __SSE2_MATH__ 1
#define __SSE2__ 1
#define __SSE_MATH__ 1
#define __SSE__ 1
#define __SSP_STRONG__ 3
#define __STDC_HOSTED__ 1
#define __STDC_IEC_559_COMPLEX__ 1
#define __STDC_IEC_559__ 1
#define __STDC_ISO_10646__ 201605L
#define __STDC_NO_THREADS__ 1
#define __STDC_UTF_16__ 1
#define __STDC_UTF_32__ 1
#define __STDC_VERSION__ 201112L
#define __STDC__ 1
#define __UINT16_C(c) c
#define __UINT16_MAX__ 0xffff
#define __UINT16_TYPE__ short unsigned int
#define __UINT32_C(c) c ## U
#define __UINT32_MAX__ 0xffffffffU
#define __UINT32_TYPE__ unsigned int
#define __UINT64_C(c) c ## UL
#define __UINT64_MAX__ 0xffffffffffffffffUL
#define __UINT64_TYPE__ long unsigned int
#define __UINT8_C(c) c
#define __UINT8_MAX__ 0xff
#define __UINT8_TYPE__ unsigned char
#define __UINTMAX_C(c) c ## UL
#define __UINTMAX_MAX__ 0xffffffffffffffffUL
#define __UINTMAX_TYPE__ long unsigned int
#define __UINTPTR_MAX__ 0xffffffffffffffffUL
#define __UINTPTR_TYPE__ long unsigned int
#define __UINT_FAST16_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST16_TYPE__ long unsigned int
#define __UINT_FAST32_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST32_TYPE__ long unsigned int
#define __UINT_FAST64_MAX__ 0xffffffffffffffffUL
#define __UINT_FAST64_TYPE__ long unsigned int
#define __UINT_FAST8_MAX__ 0xff
#define __UINT_FAST8_TYPE__ unsigned char
#define __UINT_LEAST16_MAX__ 0xffff
#define __UINT_LEAST16_TYPE__ short unsigned int
#define __UINT_LEAST32_MAX__ 0xffffffffU
#define __UINT_LEAST32_TYPE__ unsigned int
#define __UINT_LEAST64_MAX__ 0xffffffffffffffffUL
#define __UINT_LEAST64_TYPE__ long unsigned int
#define __UINT_LEAST8_MAX__ 0xff
#define __UINT_LEAST8_TYPE__ unsigned char
#define __USER_LABEL_PREFIX__
#define __VERSION__ "6.3.0 20170406"
#define __WCHAR_MAX__ 0x7fffffff
#define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
#define __WCHAR_TYPE__ int
#define __WINT_MAX__ 0xffffffffU
#define __WINT_MIN__ 0U
#define __WINT_TYPE__ unsigned int
#define __amd64 1
#define __amd64__ 1
#define __code_model_small__ 1
#define __gnu_linux__ 1
#define __has_include(STR) __has_include__(STR)
#define __has_include_next(STR) __has_include_next__(STR)
#define __k8 1
#define __k8__ 1
#define __linux 1
#define __linux__ 1
#define __pic__ 2
#define __pie__ 2
#define __unix 1
#define __unix__ 1
#define __x86_64 1
#define __x86_64__ 1
#define linux 1
#define unix 1