i use engine SDK vsiual studio cpp 2010, my codes like this:
c_ignore(_VAR(1),_VAR(0));
c_trace(XXXXXXX);
it didn't return a correct result.
but when i simplly use:
c_ignore(1,0);
c_trace(XXXXXXXX);
it's work fine.
so is the c_ignore parameters is integer in fact?

No, it's var, but your first line didn't work because the group must be higher than 1 - this restriction will be removed in the next update, as I see no reason for it. Your second call worked only because some functions, including c_ignore, can automatically detect if they get var or int parameters.