On Tue, 10 Dec 2013, Nicol TAO wrote:
I want to using #define / #undef, and want to put them in a single macro, some thing like:
#define DECALRE_TYPE(type) \ { #undef __curr_type; #define _curr_type type; }
as we know, this can not passed with CPP, but I need this logical here.
I think that you are out of luck. The preprocessor will not macro-expand one line into more than one line. Also, #s generated from macro-expansion do not count as preprocessor flags.
To get two lines from one, you need #include. #include "dcltype" Have one such file per type.
Generally, the problem comes from
#define ser_field(type, var) \ ser_new_field(tra, #type, #var, offsetof(struct_type, var))
I do not want another additional parameter in this macro like
#define ser_field(type,var,struct_type), and I want a sentence declare "current struct type" and all later work of ser_field will defaultly use this type.