Re: System/ Compiler specific macros

Robert Gamble wrote:
> vsnadagouda@xxxxxxxxx wrote:
>>
>> For one of my applications I need to know what are all the
>> predefined system/ compiler specific macros are. All these days
>> I used to use "-v" or "-#" as a compiler option to figure out
>> the required information. But recently GCC 3.4.* compilers have
>> stopped throwing out this piece of information.
>>
>> Is there any way I can write a piece of C program (or may be
>> any way) and figure out all the system and compiler specific
>> macros?
>
> This cannot portably be done, why do you think you need to do this?
>
> As far as gcc goes, from the documentation:
>
> "Assuming you have no file foo.h, the command
> touch foo.h; cpp -dM foo.h
> will show all the predefined macros."

The options used will affect that result. For ex. on my system:

[1] c:\c\junk>cpp -dM -W -Wall -ansi -pedantic empty.c
#define __HAVE_BUILTIN_SETJMP__ 1
#define __unix__ 1
#define __i386__ 1
#define __SIZE_TYPE__ long unsigned int
#define __DJGPP 2
#define __USER_LABEL_PREFIX__ _
#define __tune_pentium__ 1
#define __STDC_HOSTED__ 1
#define __MSDOS__ 1
#define DJGPP 2
#define __WCHAR_TYPE__ short unsigned int
#define __DJGPP__ 2
#define __WINT_TYPE__ int
#define __tune_i586__ 1
#define __DJGPP_MINOR__ 3
#define __STRICT_ANSI__ 1
#define __GO32__ 1
#define DJGPP_MINOR 3
#define __STDC__ 1
#define __PTRDIFF_TYPE__ int
#define __DJGPP_MINOR 3
#define __REGISTER_PREFIX__
#define __NO_INLINE__ 1
#define __i386 1
#define __VERSION__ "3.2.1"

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