c++ - Writing a Preprocessor Function: Is the syntax correct -

c++ - Writing a Preprocessor Function: Is the syntax correct -

i experimenting preprocessor function-like macros trying write macro forwards declares regular functions. when go compile says line 2 has wrong syntax.

what doing wrong?

#define forward_declare_custom_funct(fname) "int" #fname "(int id, string msg, string cmd);" forward_declare_custom_funct("abc") // line 2: should become "int abc(int id, string msg, string cmd);" void test() { abc(1, "", ""); }

the problem of quotation marks.

#define forward_declare_custom_funct(fname) "int" #fname "(int id, string msg, string cmd);"

translates (after concatenating string literals):

"int abc (int id, string msg, string cmd);"

whereas,

#define forward_declare_custom_funct(fname) int #fname (int id, string msg, string cmd);

translates to:

int "abc" (int id, string msg, string cmd);

what need simply:

#define forward_declare_custom_funct(fname) int fname (int id, string msg, string cmd);

use this:

forward_declare_custom_funct(abc)

it's text replacement. remove semicolon in macro , create user set 1 in after each utilize well, create more statement. feels more natural me.

c++ c-preprocessor