C Macros to create strings

Question

Alternative Titles (to aid search)

• Convert a preprocessor token to a string
• How to make a char string from a C

Answer 1

In C, string literals are concatenated automatically. For example,

const char * s1 = "foo" "bar";
const char * s2 = "foobar";

s1 and s2 are the same string.

So, for your problem, the answer (without token pasting) is

#ifdef __TESTING
    #define IV_DOMAIN "domain.org"
#elif __LIVE_TESTING
    #define IV_DOMAIN "test.domain.com"
#else
    #define IV_DOMAIN "domain.com"
#endif

#define IV_SECURE "secure." IV_DOMAIN
#define IV_MOBILE "m." IV_DOMAIN