Concatenate int to string using C Preprocessor

Question

I\'m trying to figure out how I can concatenate a #define\'d int to a #define\'d string using the C Preprocessor. My compiler is

Answer 1

A working way is to write MY_FILE as a parametric macro:

#define MY_FILE(x,y) "/home..." #x #y

EDIT: As noted by "Lindydancer", this solution doesn't expand macros in arguments. A more general solution is:

#define MY_FILE_(x,y) "/home..." #x #y
#define MY_FILE(x,y) MY_FILE_(x,y)

Answer 2

You can do that with BOOST_PP_STRINGIZE:

#define MAJOR_VER 2
#define MINOR_VER 6
#define MY_FILE "/home/user/.myapp" BOOST_PP_STRINGIZE(MAJOR_VER) BOOST_PP_STRINGIZE(MINOR_VER)

Answer 3

Classical C preprocessor question....

#define STR_HELPER(x) #x
#define STR(x) STR_HELPER(x)

#define MAJOR_VER 2
#define MINOR_VER 6
#define MY_FILE "/home/user/.myapp" STR(MAJOR_VER) STR(MINOR_VER)

The extra level of indirection will allow the preprocessor to expand the macros before they are converted to strings.