how to call macros from the command prompt

hi

how to call a macro from the command prompt

a macro will be expanded into C code and is not a direct function call so you cant do that

Not sure he means that...

What exactly *do* you mean?

if i have a code like this :

#ifdef TABLE_SIZE
int table[TABLE_SIZE];
#endif

how to define TABLE_SIZE in this case

You mean something like
gcc -DTABLE_SIZE=100 prog.c