This works in Borland but not on gcc. How come?Code:#ifdef __WIN32__ #define stuff printf("This is Windows") #define clear system("cls") #endif #ifdef __UNIX__ #define stuff printf("This is UNIX") #define clear system("clear") #endif #ifdef __LINUX__ #define stuff printf("This is Linux") #define clear system("clear") #endif #ifdef __MACH__ #define stuff printf("This is a Mach") #endif #ifdef __APPLE__ #define stuff printf("This is a Apple") #endif main(){ printf("%s\n",stuff); }
I'm not sure if the __UNIX__ and __LINUX__
defines are right. It's compiler dependant anyways but most
compilers have a way you can #define stuft by the command line
so like you can do
gcc file.c -DUNIX which defines UNIX.
by dooing info gcc, you can read the documentation on target
macros.
im surprised that it runs on anything.....
look at your macros...
#ifdef __WIN32__
#define stuff printf("This is Windows")
#define clear system("cls")
#endif
main(){
printf("%s\n",stuff);
}
now the printf statement will expand to :-
printf("%s\n",printf("This is windows"));
does that look right to you!
Free the weed!! Class B to class C is not good enough!!
And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi
There was a typo.
it should of beenand the same for the rest. In linux in totally ignores this stuff.Code:#ifdef __WIN32__ #define stuff "This is Windows" #define clear system("cls") #endif
Given your other typo's, did
printf("%s\n",stuff);
really have a \n on the end?
If output doesn't end with a \n, you may not see the output, though it ought to flush stdout at program exit.
Use
gcc -E prog.c > prog.i
to just run the pre-processor, to find out what all those #defines etc expand to.
Is the result what you expect?
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
