C embedded questions (3): Advantages of a macro over a function

Advantages of a macro over a function

Macro gets to see the Compilation environment, so it can expand
____TIME__ __FILE__ #defines. It is expanded by the preprocessor.

For example

It can’t do this without macros:

#define PRINT(EXPR) printf( #EXPR “=%d\n”, EXPR) 
PRINT( 5+6*7 ) // expands into printf(”5+6*7=%d”, 5+6*7 ); 

You can define your mini language with macros:

#define strequal(A,B) (!strcmp(A,B)) 

Macros are a necessary evils of life. The purists don’t like them, but

without it no real work gets done.