为win32 && linux定义清除函数

Question

My question should not be too hard to answer:

I am trying to write a C program just to train up some C skills. However I can't tell on which system this program will run in the future.

I want to make sure I have covered both Unix and DOS systems.

I am trying to do it like this:

#ifdef _WIN32
   #define clear()
       system("cls");
#endif // _WIN32

#ifdef linux
    #define clear()
       system("clear");
#endif // linux

This seems to be wrong, as it tells me

expected declaration specifiers or '...' before string constant"

Although I'm not sure if I am doing it right at all with this definitions (I could include 2 separate headers here for example >> more memory used)

There must be kind of a hard newbish syntax error here.

Answer 1

Macro expansion should be on the same line as the macro name. If you really want them over two lines, use \\ to "escape" the newline.

#ifdef _WIN32
#define clear() system("cls");
#endif // _WIN32

#ifdef linux
#define clear() system("clear");
#endif // linux

or

#ifdef _WIN32
#define clear() \
system("cls");
#endif // _WIN32

#ifdef linux
#define clear() \
system("clear");
#endif // linux