__SHORT_FILE__ Macro

short_file.cpp

#include <stdio.h>

using cstr = const char * const;
static cstr constexpr past_last_slash(cstr str, cstr last_slash)
{
    return
        *str == '\0' ? last_slash :
        *str == '/'  ? past_last_slash(str + 1, str + 1)
                     : past_last_slash(str + 1, last_slash);
}

static cstr constexpr past_last_slash(cstr str) { return past_last_slash(str, str); }

#define __SHORT_FILE__ ({constexpr cstr sf__ {past_last_slash(__FILE__)}; sf__;})

int main()
{
    puts(__SHORT_FILE__);
    return 0;
}

ah. right. that's c++14 only. and yes, more a matter of style